Pioneer Car Stereo System SX 636 Poptronics 1974 11

User Manual: Pioneer Car Stereo System SX-636

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:peed while a record is playing. !kith of
nese sophisticated units are even
;quipped with a
'trobe light directed
the strobe marks
r easy viewing.
Pioneer's engineers r-
tally think of -
everything.
"lectronic speed adjust -
lent for each speed
Xutomatic features without.
Mutomatic drawbacks
If you prefer to let your tonearm and -
urntable do all the work, consider Pioneer's_
TT
3
o°
- _
F o ,
,.linkages to provide the necessary ton-eel-ní_ -
cycling motion, the PL-A45D uses a - -
- `separate precision gear moto just to InoVe
the tonearmin accordance with your
`instructions, Its,áther 4 -pole synchrortous - -
motor is free to ' ''The tradition of mexcelled
drive only tie` ' - - performance c 5
12 -inch aluminum. - , _` Still, all of these features and refine -
alloy die-cast plattsr- 7`tnents alone do -not guarantee the perform -
without interrúption- -;ance specificatrors of Pioneer's new
or change of torque --turntables. Each tonearm an,d turntable
and speed. _ - pletter combináticn is shock mounted in
-'ita"specialty desigted natural grain cabinet
Automatic operation? . ' (with hinged dust cover). Precision machin-
manual precision
Ill new PL-A45D. With it you can play your a - = - - _ -zing of all rotatikn21 parts of each unit, plus
cords without ever touching the tonearm. ' _ ,°Superb S -Shaped toneartns' . _ -a prográm of continuous quality control
nlike other single play automatics which - ;. ' for better tracking - - -.in-sure that each Pioneer turntable will meet
(epend upon complicated mechanical _ - 4 -;or: exceed its published specifications -
Ile that's right for you.
fPL-A45D PL -51A
Belt 4Direct
pole synch. DC Servo
±2%
pre than 47d1 More than 55dB
(WRMS) 0.06% (WRMS)
latic Bal. "S" Static Bal. "S"
' 811M6" 8116l?
12" . 121/4"
i;
The tonearm of every
, Pioneer turntable system
is the "S-shaped"
PL 71 - design, for optimum
Direct -statically balanced and
DC Servo ',all use adjustable counter -
2% weights with direct read -
More than 60dB = out of tracking force. All
0.05% (WRMS) have adjustable"
Static Bal. "S",, - anti -skate contrcl and
oil -damped cueing for
the gentlest application
groove tracking- All are
12Y4" of stylus tip to record
xHbs. 3 oz. 3 lbs. 1 oz. 3 lbs. 8 oz.
$169.95 .
- $249.95 $299.95
o
a
S-sháped tonearm.
for ideal tracking
in cartridge"shells
insure positive electrical contact and". -
optimum stylus position and angle for.lower_1
distortion and reduced record wear. =
groove. Lightweight plug -
a time honored;,tradition with all Pioneer
,ccmpon-enis,
:Manual turñtabtes-choice of
- the professionals
Engineers, experts and enthusiasts
agree: to get the best performance, you
-`need a manual turntable. And to get the best
-manual turntab e, you need a Pioneer.
Every Pioneer manual turntable offers a
level of precision and performance un -
_paralleled in itspe_ice range. And every
is atotai system - complete with dust
-cóver and b99e4-and designed for
';years ofproféssianal trouble -free sound
reproduttiorl.
AmericanRadioHistory.Com
--
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st manual
t a Pióñe
.
The manual turntable is rapidly
becoming the first choice of hi-fi erthusiasts
'everywhere. The reason why is quite simple.
Today's enthusiasts are more knowledge-
able, more sophisticated and more involved
with their music. And only the manual
turntable can provide the involvement
and performance they demand. -
At Pioneer, this trend comes as no
surprise. We have long recognized the
superiority of the manual turntable. And
long recognized a simple fact: a record
changer in no way improves performance.
Lt can detract from it.
As a result, we now offer the finest and
most complete line of manual turntables
available. Manual turntables that are
cesigned with the needs of today's hi-fi
enthusiast in mind. Turntables that are
engineered for precision response.
When you get right down to it, good
record playing equipment really has only
two requirements: uniform rotation of a
turntable, and accurate tracing of a record
groove by a tonearm and its cartridge.
Pioneer's engineers have long recog-
nized that these requirements are best met
by single -play turntables and precision
engineered tonearms. Our five new belt -
drive and direct -drive turnable systems
mean you needn't settle for the higher wow
t
urntab e.
and flutter and the poorer signal=to-noise
ratios (rumble) of record changers. Whether -
you've budgeted $100 or $300 for this vital
element of your high fidelity system, there's -
a Pioneer turntable that outperforms any
record changer in its price class:
Cónsider the performance advantages -
Belt -drive, featured in Pioneer's PL -10,
PL -12D and PL-A45D, means smoother,
more uniform platter rotation than can be -
acnieved with typical idler-wheel/pulley
arrangements normally found in record-.
chargers. Even changers equipped with
synchronous motors transmit .
vibration to the turntable platter. This is
picked up as low -frequency rumble by the
tonearm and cartridge. By driving the platter
with a precision -finished belt, vibration
is effectively absorbed before it can be -
translated to audible rumble.
Belt -drive for
'
Direct -drive motoi:
rumble -free rotation reduces friction
Pioneer's direct -drive models, PL -51A
and PL -71 go even a step further in achiev-
ing noise -free, precision platter rotation.
The DC electronically controlled servo-
motors used in these models rotate at
exactly the required 331/2 or 45 rpm platter
speed. Their shafts are directly connected
tc the center of the turntable, with no inter-
mediate pulleys or other speed reduction
devices. This means no extra friction -
producing bearing surfaces.
- Because of the unique technology
embodied in these new, direct -drive motors, ` 1 -
it's possible to control their speed electron-
icalry. This is more precise than any
mechanical drive system. Both our PL -51A
and PL -71 offer individual pitch control for
both 331/3 and 45 rpm speeds. Their turn-
table platters are edge -fitted with strobo-
scopic marks, so you can adjust precise
b
l _4
Choose the Pioneer turnta
Model PL -10 PL -12D
Drive system Belt Belt
motor _
Speed control
SI N -(Rumble)
Wow & Flutter
Tonearm Type
Tonéarm Length
ive
Is Turntable
Diameter
4 -pole synch:
More than 47dB
0.1% IWRMS)
Static Bal. "S"
óF/Í6"
12"
4 -pole synch. 4
More than 47dB M
0.1% (WRMS) 01
Static Bal. "S" Si
81]16"
12"
Turntable"
- Weight.
_ Pnce:
2 lbs. 3 oz.
$99.95
a lbs. 3 oz.
$119.95
g AmericanRadioHistory.Com
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U.S. Pioneer Electronics Corp., 75 Oxford Drive, Moonachie, New Jersey 07074
West: 13300 S. EstreÍla, Los Angeles,90248/Midwest: 1500 Greenleaf, Elk Grove Village, Ill 60007/Canada: S.H. Parker Co
CIRCLE NO. 41 ON READERS SERVICE -CARD AmericanRadioHistory.Com
TM
TM
Pickering cartridges feature low frequency
tracking and high frequency tracing ability*
Pickering offers you "The Best of Both
Worlds" in discrete 4 -channel and in
stereo cartridges. These cartridges have
been specifically designed and engineered
to peak specification and performance
characteristics. They possess traceAbility,
vital for both stereo and discrete playback.
For example, take the case of discrete
s -
(B)
2
(C)
-
J
playback. You are looking at a model of a
discrete groove, magnified 3,000 times
(figure A). You can sée it is made Up of
complex groove undulations. This makes
the demands on the cartridge and its
stylus much greater than ever before. The
left side of the groove possesses all of the
information recorded on the left side of the
room, and the right side likewise. The
stereo signals for the front speakers are
represented by the broad sweeps (figure
B), and the special discrete high fre-
quency tone carrier is represented by the
wiggles on the same groove walls (figure
C). This high frequency carrier centered
at 30,000 Hz, demands a superior stylus
assembly (and shape of the tip) which we
call our QuadrahedralT" another Pickering
exclusive which makes it possible for the
stylus to trace both the stereo and dis-
crete signals in the groove.
So, the QuadrahedralT" stylus picks up
CIRCLE NO. 30 ON READERS SERVICE CARD
(A)
all 4 signals, which the computerized de-
modulator sorts for the amplifier, which in
turn transmits the sound to the proper
speaker.
So, whether you look forward to the
fabulous reality of discrete 4 -channel
sound in your home, or the finest stereo
to satisfy your listening taste - depend on
the traceAbility of Pickering cartridges to
make possible "The Best of Both Worlds".
. . the world of stereo and matrix, and
the world of discrete 4 -channel.
For further information write to
Pickering & Co., Inc., Dept. PE
Sunnyside Blvd., Plainview, New York 11803
PICKERING
"for those who can ihearl the difference"
TM-PICKERING TRADEMARK
POPULAR ELECTRONICS
AmericanRadioHistory.Com
NOVEMBER 1974 VOLUME 6, NUMBER 5
!oiu,,a. ectronics
WORLDS LARGEST- SELLING ELECTRONICS MAGAZINE
FEATURE ARTICLES
HOW THE NEW FTC HI-FI RULES AFFECT YOU! Leonard Feldman 39
The buyer must still be wary of power claims.
WHAT'S NEW IN COLOR TV RECEIVERS FOR 1975 Art Margolis
NEW DOLBY -ENCODED FM BROADCASTS
How new FCC rules affect FM reception
BASIC DIGITAL LOGIC COURSE Forrest M. Mims & H. Edward Roberts 57
Part 2: Concepts and circuits
CAREER OPPORTUNITIES FOR THE TECH REP Allan C. Stover
COMPUTER TERMINALS ARE COMING Leslie Solomon
Time savers for the home and small business
ENGLISH LANGUAGE SHORTWAVE BROADCASTS Roger Legge 79
November to February
THE SIMPLEST TEST GEAR John T. Frye 88
Test probes can solve many service problems
41
46
69
78
CONSTRUCTION STORIES
BUILD A LASER TV SYSTEM Giancarlo Punis & Joseph O'Donnell 32
Transmit and receive BIW pictures on a laser beam
BUILD A DIRECT -CONVERSION COMMUNICATION RECEIVER Jim White 48
Good performance at a fraction of the cost of a superhet
MEASURE LOW MILLIVOLTS WITH A MULTIMETIER John F. Hollabaugh 52
Range expander increases sensitivity by X10 or X100
BUILD A VERSATILE DIGITAL LED THERMOMETER Thomas R. Fox 54
COLUMNS
HOBBY SCENE Editorial Staff 17
STEREO SCENE Ralph Hodges 22
Blazing speakers
DX LISTENING Glenn Hauser 80
"Secret" shortwave stations
CB SCENE Len Buckwalter 86
CB to the rescue
SOLID STATE Lou Garner 90
Circuits using field-effect transistors
PRODUCT TEST REPORTS
PIONEER MODEL SX-636 AM/STEREO FM RECEIVER
ROYCE MODEL 1-600 MOBILE CB TRANSCEIVER
PICKERING MODEL OA -3 STEREO HEADPHONES
DRAKE MODEL SPR-4 COMMUNICATIONS RECEIVER
AMERICAN CIRCUITS & SYSTEMS MODEL MK1 FUNCTION GENERATOR
DEPARTMENTS
EDITORIAL Art Salsberg
Run It Up The Flagpole
LETTERS
NEW PRODUCTS
NEW LITERATURE
NEWS HIGHLIGHTS
POPULAR ELECTRONICS, November 1974, Volume 6, Number 5 Pub-
lished monthly at One Park Avenue, New York, NY 10016. One year sub-
scription rate for U.S.. Possessions and Canada, $6.98; all other countries,
$8.98. Second class Postage paid at New York. NY and at additional
mailing offices. Authorized as second class mail by the Post Office De-
partment, Ottawa, Canada and for payment of postage in cash. Subscrip-
tion service and Forms 3579; P.O. Box 2774, Boulder, CO 80302.
POPULAR ELECTRONICS Including ELECTRONICS WORLD, Trade
Mark Registered. Indexed in the Reader's Guide to Periodical Literature.
COPYRIGHT C 1974 BY ZIFF-DAVIS PUBLISHING COMPANY. ALL
RIGHTS RESERVED.
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61 66 68
4
6
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Ziff -Davis also publishes Boating, Car and Driver, Cycle, Flying, Mod-
ern Bride, Popular Photography, Skiing and Stereo Review.
Forms 3579 and all subscription correspondence should be addressed
to POPULAR ELECTRONICS, Circulation Dept., P. O. Box 2774, Boulder,
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Editorial contributions must be accompanied by return posrage and
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NOVEMBER 1974 3
AmericanRadioHistory.Com
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NOVEMBER 1974 CIRCLE NO. 6 ON READERS SERVICE CARD 5
AmericanRadioHistory.Com
FEEDBACK ON DOUBLE -SIDED PC BOARDS
The process detailed in "How To Make
Double -Sided PC Boards" (June 1974) can
be simplified in the following manner:
First, photo -reverse the exposure masks.
Use IC -pad holes as references to align the
reversed films, and tape the edges together
along three sides. Punch holes through
both films in unused areas (preferably in
each corner) of the layout.
In a safe -lighted area, slide the pc blank
between the films and apply small squares
of transparent tape over the punched holes
to secure the film to both sides of the blank.
Expose the board, one side at a time, using
a photographic contact printer with foam
backing. Finally, remove the tape and de-
velop and etch the blank.
GERALD G. CRAMM
Quantico, Va.
I feel I must criticize Mr. Burawa's state-
ment that "If you can trace a circuit, you
can design any type of pc board." I am
afraid that many readers are going to get
themselves into difficulties if they follow
this advice. Pc boards are not a toy for the
unskilled. Having been in the pc -board de-
sign field since its inception, I can attest
that it takes many hours of training to ac-
quire the design knowledge required for
making pc boards.
Also lacking in the article was any men-
tion of the fact that pads or land areas are
chosen in relation to the hole size for the
component lead or that there are strict
rules on clearances between components
and the foil conductors. The greater the
packaging density, the more problems will
be encountered and the more you must rely
upon the rules that govern pc designs.
Hence, without a formal education in de-
sign, expensive trial and error are going to
cause short tempers.
RICHARD MAYER
Crown Point, N.Y.
"I do not deny that formal training would
better prepare the experimenter for tack-
ling pc board design and fabrication. But I
also feel that it is not absolutely necessary
in the great majority of cases. I contend
that if you can trace a circuit, you can de-
sign just about any type of pc board. I
would only add that good layout proce-
dures be practiced in high -gain, r -f, and
other critical designs to avoid crosstalk,
feedback, etc. -Author
LINEARS ON CB ARE A NO -NO
I would very much appreciate any infor-
mation you can pass on with regard to
using a linear amplifier with my CB trans-
ceiver. Name Withheld
The best information we can pass on is
don't. The use of a linear power amplifier
with a CB transceiver is forbidden by the
FCC rules.
Ampzilla
here...
Why spend $750 to $1200 dollars for
' an amplifier? The Great
American Sound Company
t sells one with a full comple-
mentary series connected out-
put for much less. In short
(AMPZILLA is here. In the
September 1974 Popular Elec-
...s.177117.7;1111,5°.. itronics, Hirsch -Houck Labs
'... solidly in the audio
"'!monster amplifier class .
'using 8 ohm loads . .. THD was less
ysr z than 0.01% for all power levels ... up
to 200 watts .... 'Iper channel). . all in
all we cannot imagine a less expensive way of obtaining several hun-
dred watts.' Yes, we, your friendly GAS company, have the goods
complete with a fan for ultra cool operation. Available with direct read -
1 ing power meters in kit ($375) or fully assembled ($525). Also the
same amp but no meters in kit ($3401 and assembled ($475). Write us
for complete specs, or read Popular Electronics, September 1974.
Available directly from
THE GREAT AMERICAN SOUND COMPANY, INC.
8780 Shoreham Drive, West Hollywood, California 90069
CIRCLE NO. 18 ON READERS SERVICE CARD
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O Charge my K & B account Payment in amount of $ enclosed
Charge my Master Charge or Bank Americard Expiration date
Illinois residents add 5% tax. Free delivery in Chicago and suburbs. Elsewhere add 40' per book mailing &
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NOVEMBER 1974
CIRCLE NO. 23 ON READERS SERVICE CARD 7
AmericanRadioHistory.Com
y
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Almost half of the successful TV servicemen have ;
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than any other home study school. More than twice as many!
8 POPULAR ELECTRONICS
AmericanRadioHistory.Com
Not only that, but a national
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Why? Perhaps NRI's 60 -year
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NOVEMBER 1974 11
1/4
AmericanRadioHistory.Com
'I got,
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t.
I, Dick Blake, sent off to the
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clude $1 for postage, those great
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following: their new 64 -page catalog
of professional products for music-
ians, or the 1975 edition of the Music
Machine Almanac, which is a 185 -page
institutional guide to stereo equip-
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and specifications for over 40 brands!
Sells on the newsstands for $1.95 - so
it's a good deal. Do it today!
WAREHOUSE SOUND CO.
BOX S SAN LUIS OBISPO
CA. 93405 (805) 543-2330
:2MS 0490
Railroad Square, Box S
San Luis Obispo, CA. 93405
(805) 543-2330
name
address
city/state
zip
Also enclosed is $1.00 for:
(check one)
Professional Products Catalog
01975 Music Machine Almanac K-2
New Products
Additional information on new products
covered in this section is available from
the manufacturers. Either circle the item's
code number on the Reader Service Card
inside the back cover or write to the man-
ufacturer at the address given.
FISHER 4 -CHANNEL RECEIVER
The Fisher Studio Standard Model 334
4 -channel receiver boasts 40 watts
rms/channel with all channels driven into
8 -ohm loads and an IHF power bandwidth
of 30 to 22,000 Hz at 1 percent IM and 0.8
percent THD. It features built-in SO and
íiPJ iflfi.fk;tntu t3 nM1tia.Ka. r
nAOÓÓR i o i orL{,
CD -4 decoding circuitry. Besides husky
power rating, the receiver also has a "joy-
stick" channel -balance control, loudness
contour that is automatically disengaged
when the output level is raised, and a sensi-
tive (2-0) tuner. If stereo operation is de-
sired, the amplifiers can be "strapped" to
double the power per channel. Other fea-
tures include Baxandall-type tone con-
trols, FM muting, tape monitoring circuitry,
output jacks for 4 -channel recorders, tun-
ing meter with Fisher's "Stereo Beacon,"
and an AM tuner.
CIRCLE NO. 70 ON READER SERVICE CARD
PEARCE-SIMPSON CB TRANSCEIVER
The Puma 23B is a 23 -channel AM mobile
CB rig (crystals supplied) from Pearce -
Simpson. Its S/r-f meter glows amber on
receive, red on transmit, and flashes bright
red when fully modulated. A switch permits
selection of r -f or PA output. The transmit-
ter operates at the legal power limit. A
dual -conversion receiver with 0.5-µV sen-
sitivity, with a crystal filter for selectivity
and an automatic noise limiter, simplify the
task of receiving signals on the crowded
11.J
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I
channels. A noise -cancelling microphone,
mobile mounting bracket, and external
power cord are supplied with the trans-
ceiver.
CIRCLE NO. 71 ON READER SERVICE CARD
JBL DECADE SERIES SPEAKER SYSTEM
The Model L36 is a moderately -priced
three-way speaker system that incorpo-
rates some of the hardware that comprises
the JBL Century L100 and professional
Model 4311 Studio Monitor systems. The
L36 contains a 10 -in. (25.4 -cm) woofer with
a 2.5 -lb (about 1 -kg) magnet, 5 -in.
(12.7 -cm) midrange driver, and a 1.4 -in.
(3.56 -cm) tweeter. Crossover frequencies
are at 1500 and 6000 Hz. Nominal impe-
dance of the system is 8 ohms. Power
capacity is rated at 50 watts rms of con-
tinuous program material, requiring 10
watts rms minimum drive power. The en-
closure uses a ducted -port design and
comes finished in natural oak with fabric
color options. The system measures 24 in.
by 135/e in. by 13V2 in. (61 x 34.6 x 34.3 cm)
and weighs 45 lbs (20.5 kg). Retail price is
$198.
CIRCLE NO.72 ON READER SERVICE CARD
TECHNICS SPEAKER SYSTEM
Technics by Panasonic has introduced
a new series of speaker systems that in-
cludes bookshelf and floor -standing mod-
els. The top -of -the -line Model T-500 is a
r.l ~-t1!
four-way, seven -driver system that features
a frequency response of 35 to 20,000 Hz
±3 dB and handles between 10 watts
minimum and 100 watts maximum pro-
gram power. Frequencies up to 2000 Hz are
covered by two 10 -in. (25.4 -cm) woofers, a
5 -in. (12.7 -cm) driver handles the mid-
range, and a pair of wide -dispersion tweet-
ers take care of the highs. Frequencies
above 8000 Hz are reproduced by an an-
gled super tweeter assembly composed of
two 2 -in. (5.1 -cm) transducers with a 180°
dispersion angle. Two -position level con-
trols are provided for the midrange and
tweeter.
CIRCLE NO. 73 ON READER SERVICE CARD
CONWAY MASTERANGER
The Model 639 Masteranger from Conway
is an unusually versatile multimeter that
covers 93 ranges and 11 parameters. It fea-
tures a FET front end for dc volts, 100-
12 POPULAR ELECTRONICS
AmericanRadioHistory.Com
C MOS
4000AE
4001AE
4002AE
4004AE
4006AE
4007AE
4008AE
4009 A E
4010AE
4011AE
4012AE
4013AE
4014AE
4015AE
4016AE
4017AE
4018A
4019AE
4020AE
4021 A E
4022AE
402 3A E
4024AE
4025AE
4026A E
4027AE
4028AE
4029AE
4030AE
4035AE
4037AE
4040AE
4041 A E
4042AE
4043AE
4044A E
4048 A E
4049AE
4050AE
4051AE
4056AE
4060AE
4069 AE
4076A E
$ .55
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.60
5.90
3.90
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3.60
.95
1.20
.55
.55
1.40
3.80
3.80
1.15
2.95
3.20
1.30
4.20
3.80
2.95
.55
2.30
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9.90
1.85
2.95
5.40
1.25
1.80
4.00
4.70
3.35
2.95
2.95
2.95
1.50
1.35
1.35
5.40
3.50
4.95
.90
4.30
SchottkyL
SN74S00N
SN74S02N
SN74S03N
SN74SO4N
SN74S08N
SN74S10N
SN74S11N
SN74S20N
SN74S30N
SN 74S32 N
SN74S40N
$N74541N
SN74S64N
SN74S74N
SN74S85N
SN74S86N
SN745112N
SN74S113N
SN74S133N
SN74S138N
SN74S139N
SN74S140N
SN74S151N
SN74S153N
SN74S154N
SN74S157N
SN74S158N
SN74S160N
SN74S161N
SN74S174N
SN74S175N
SN74S181N
SN74S189N
SN74S194N
SN74S195N
SN74S251N
SN74S253N
SN74S275N
SN74S258N
SN74S260N
SN74S280N
SN74S289N
93S10
93S16
93S21
93S22
93S48
S .80
.80
.80
.80
.80
.80
.80
.80
.80
.80
.80
.80
.80
1.30
6.10
2.90
2.50
1.50
1.00
4.50
4.20
1.00
3.30
3.30
3.40
3.00
3.00
6.60
6.60
4.75
5.00
12.50
5.10
4.40
4.40
4.20
4.20
3.20
3.70
.90
5.70
5.00
6.80
6.80
3.50
3.20
3.70
HIGH
SPEED TTL
74H00N .34
74H01N .49
74H04N .36
74H05N .38
74H08N .44
74H 10N .44
74H11N .44
74H 15N .38
74H2ON .39
741-140N .36
74H74N .69
instrument at a fraction of
the cost of conventional unit.
Kit includes two XR205 IC's,
data & applications, PC board
(etched & drilled, ready for
assembly) and detailed instruc-
tions.
Audio Amps
LM352: 6-15V, 1.15W, 8Si 1.60
LM354A: 6.27V, 2.80W, 8Si 2.50
TAA611612: 6-15V, 1.15W, 8S2 1.60
TAA621Al2: 6-27V, 1.40W, 82 2.00
TBA641811: 6-18V, 2.20W, 42 3.00
TBA800: 5-30V, 4.70W, 8Si 2.20
TBA810AS: 4-20V, 2.50W 4$Z 3.00
TBA820: 3.16V, 0.75W, 45i 1.70
TCA830: 5.20V, 2.00W, 4S2 2.20
TCA940: 6-24V, 6.50W, 82 4.40
HYBRID
Po' AMPLIFIERS
DIU/AL LOW
NOISE
OP nMP
LM331 N:
V¡o = 6mV
Ile = 1000nA
I b = 2000nA
Noise = 1.5dB
$2.20
FM Stereo
Demodulator
XR1310 $3.90
L! Power
SI -1010Y
SI -1025E
SI -1050E
Waveform Generator Kit
XR205K Only $28.00 Voltage
Here's a highly versatile lab Regulators
LM100H $5.50
LM104H 6.50
LM105H 5.10
LM105F 8.50
LM109H 9.50
LM109K 6.30
LM200H 3.80
LM204H 4.70
LM205H 3.00
LM209H 3.50
LM209K 3.70
LM300H .90
LM300N 1.40
LM304H 1.40
LM305H 1.10
LM305AH 1.40
LM305N 1.20
LM309H 1.75
LM309K 1.95
LM335 2.30
LM336 2.40
LM337 2.40
LM340-05K 2.60
LM340-06K 2.60
LM340-08K 2.60
LM340-12K 2.60
LM340-15K 2.60
LM340-18K 2.60
LM340-24K 2.60
LM723H 1.30
LM723D 3.90
LM723CH .80
RMS IHF Price LM723CN .75
10911 25W $ 6.40 L129 1.50
25W 65W 18.00 L130 1.50
50W 120W 25.40 L131 1.50
\\\\-O`s
, ,
z
You deserve
watch
with liquid crystal display.
Beautiful, reliable & accur-
ate. $149.00 plus $2.50
for shipping & handling.
Memories
P1101A $7.00
P1101A1 8.50
P1402A 8.50
P2102 16.00
P3101 5.50
P3101A 5.50
MM6560N 5.00
MM6561N 5.00
DM8599N 5.00
93403 5.00
Decoded Read/
Write RAM
P1103 $7.50
N",arrYA\\rr\4
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PREMIUM QUALITY COMPONENTS
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. ^, a r`
7400N
7401N
7402N
7403N
7404N
7405N
7406N
7407N
7408N
7409N
7410N
7411N
7412N
7413N
7414N
7416N
7417N
7420N
7421N
7423N
7425N
7426N
7427N
7428N
7430N
7432N
7433N
- 7437N
7438N
7439N
7440N
7441 AN
7442N
7445N
7447N
7448N
7450N
7451N
7453N
7454N
7460N
7470N
7472N
7473N
7474N
.18
.27
.23
.23
.25
.29
.42
.49
.24
.54
.24 .29
.51 .79
2.81 .47
.64
.25
.51
.49
.49 .49
.54
.51
.23
.29
.61
.49
.49
1.01
.23
1.16
.99
1.14
1.39
1.29
.23
.29
.26
.26
.24
.31 .39
.47
.47
7400N TTL
7475N
7476N
7480N
7481N
7482N
7483N
7484N
7485N
7486N
7489N
7490N
7491N
7492N
7493N
7493AN
7494N
7495N
7495AN
7496N
7497N
741 OON
74105N
74107N
74108N
74109N
74110N
74111N
74114N
74115N
74118N
74119N
74121N
74122N
74123N
74125N
74126N
74128N
74132N
74136N
74141N
74145N
74147N
741 48N
.79
.59
.66
1.21
1.01
1.01
3.01
2.49 .49
2.99
.79
1.29 .84
.84
.86
1.29
.99
1.51
1.09
1.51
1 .65
.54
.49
.91
.91
.71 .91
.91
.91
.91
.81
.59
.89
.96
1.39
1.39
1.21
2.05
.91
1.89
1.79
2.95
3.55
74150N
74151N
74152N
74153N
74154N
74155N
74156N
74157N
74158N
74160N
74161N
74162N
74163N
74164N
74165N
74166N
74170N
74173N
74174N
74175N
74176N
74177N
74180N
74181N
74182N
74184N
74185N
74190N
74191N
74192N
74193N
74194N
74195N
74196N
74197N
74198N
74199N
74200N
74221N
74251N
74278N
74279 N
74293N
74298N
1.14
.89
2.25
1.12
1.64
1.49
1.49
1.26
1.54
1.89
1.59
2.05
1.59
1.89
1.89
1.98
2.55
1.79
1 .52
1.92
1.69
1.69
2.49
3.85
1.19
2.89
2.29
2.89
2.89
1.49
1.39
1.89
.99
2.39
2.39
2.59
4.48
5.05
1.75
1.75
2.95
.92
.92
2.55
LOW
POWER TTL
74LOON
74L02N
74L03N
74L04N
74L10N
74L2ON
74L42N
74L47N
74 L51
74L73N
74L74N
74L9ON
74L93N
74L95N
93L00
93L01
93L08
93L 09
93L10
93L11
93L12
93L 14
93L 16
93L18
93L21
93L22
93L24
93L28
93L34
93L38
93L40
93L41
93L60
93L66
.34
.34
.39
.39 .34
.39
1.62
1.62
.34
.74 .89
1.62
1.74
1.62
1.50
1.60
3.40
1.80
2.80
4.20
1.80
1.70
3.20
3.50
1.50
1.80
2.80
3.70
4.00
4.20
6.50
6.50
3.00
2.70
MIN. ORDER
$10.00
COMPZJT'ER
IPTTERF7Pa+CE
DM8820N 4.00
DM8820AN 6.50
DM8830N 4.50
DM8831N 5.00
DM8832N 5.00
9600 1.30
9601 1.30
9602
9614
9615
9616
9617
9620
9621
2.00
3.00
3.00
4.50
3.00
3.50
3.00
PULSE GENERATOR
Interdesign 1101: 0.1Hz-2MHz,
0-5V Output, var. width, line or
battery operation. $159.00.
Power Regulators
LM335K: 5V, 600mA 2.40
LM336K: 12V, 500mA 3.50
LM337K: 15V, 450mA 3.60
Power Transistors
BU204
8U205
BU206
BU207
BU208
BU209
1300V
1500V
1700V
1300V
1500V
1700V
4.14
4.95
5.94
5.85
6.93
8.64
TECHNICAL LITERATURE
5.50 per item
Contains literature for all products
SALES TAX: California residents add 6%; Canadian
residents add 12% federal sales tax, and add 5% in B.C.
SEND CHECK OR MONEY ORDER (NO. C.O.D.) TO:
, - - r, A' ... ,
P. O. Box 2208P, Culver City, CA. ff0 23
'r
LED's
.125"dia.
209 Red $ .25
209 Yellow .35
209 Green .35
.160"dia.
216 Red .25
216 Yellow .30
216 Green .30
.200"dia.
220 Red
220 Yellow
220 Green
Displays
SLA I
SLA11
SLA21
SL A2
SLA 12
SLA22
SLA3
SLA4
.25
.30
.30
Red 2.25
Green 4.25
4.25
±1 Red 2.25
±1 Green 2.25
2.25
Red 7.50
Red 7.50
Optoisolator
MCT2 1.45
Linear ICI
LM 301A
LM301 AM
LM301 AN
LM302H
LM 302 N
LM306H
LM307H
LM 307M
LM 308 H
LM308AH
LM31oH
LM311 H
LM318H
LM555CM
LM709CH
LM709CN
LM710CH
LM710CN
LM725CH
LM733CH
LM733CN
LM741CH
LM741 CM
LM747CH
LM747CN
LM748CN
LM3046CN
LM3054CN
TO -5 $.90
Mini -dip .75
Dip 1.10
TO -5 .95
Dip 1.40
TO -5 2.80
TO -5 .90
Mini -dip .90
TO -5 1.20
TO -5 5.00
TO -5 1,40
TO -5 1.70
TO -5 2.50
Mini -dip .95
TO -5 .45
Dip .45
TO -5 .60
Dip .75
TO -5 5.00
TO -5 1.50
Dip 1.50
TO -5 .45
Mini -dip .44
TO -5 1.90
Dip .90
Dip .40
Dip .95
Dip 1.50
Phase Locked Loops
LM567CM Mini -dip 2.00
IC sockets
8p¡n DIL .22
14 pin DIL .26
16 pin DIL .29
24 pin DIL .75
28 pin DIL 1.10
36 pin DIL 1.70
40 pin DIL 1.90
Teflon
3 pin TO -5 .55
4 pin TO -5 .65
6 pin TO -5 .90
B pin TO -5 1.10
10 pin TO -5 1.40
Shift Registers
1402A $ 8.50
1403A 6.00
1404A 6.00
1405A 4.50
1406 6.00
1407 6.00
1506 3.00
1507 3.00
2505K 4.00
2512K 5.50
2524V 4.00
2525V 5.50
2807 4.00
2808 5.50
TMS3114 8.20
MM5055N 5.00
MM5056H 5.00
MM5057N 5.00
NOVEMBER 1974 13
AmericanRadioHistory.Com
cre i,
r,
How else \vould you describe a
preamplifier with:
A Peak Unlimiter that restores
dynamics lost in recording to
closely approximate the original.
A Downward Expander that reads
"gain riding" and expands
dynamics down to precisely the
intended level.
An AutoCorrelator that makes
record/tape hiss and FM broadcast
noise virtually vanish without
affecting musical content.
Plus an Active Equalizer that gives
you flat energy distribution over
the full audio spectrum, Joystick
Balance and Step Tone Controls
that allow precise music tailoring
to your listening environment and
SQW' and Phase Linear differential
logic for Quad Sound.
The 4000 is an advanced stereo
preamp that actually puts back in
what recording studios take out ...
lets your music (at last) reach life -like
levels without distortion ... lets you
(for the first time) hear your music
from a silent background. It is, in a
word, incredible. Ask your dealer
for an audition.
Price: $599
Cabinet: $37
Warranty: 3 years, parts & labor.
4000
THE POWERFUL DIFFERENCE
PHASE LINEAR CORPORATION
P.O. Box 1335 Lynnwood, Wash. 98036
*SQ is a trademark of CBS Labs, Inc.
CIRCLE NO. 45 ON READERS SERVICE CARD
14
megohms input impedance, and an excep-
tionally large mirrored meter movement
scale. Although the instrument is designed
to be battery operated, an accessory power
supply permits line operation. With op-
tional probes, ranges are further extenced,
and they permit r -f voltage and tempera-
ture to be measured. A zero scale permits
null detection and galvanometer opera-
tion. The tester can also be used for in -
circuit resistance checks on semi-
conductors without damaging them. Accu-
racy is claimed to range from ±-1.5 percent
for ac and dc voltages up to 1500 volts to -±5
percent for r -f. R -f, HV, arid peak -to -peak
probes, external high -current shunt, ac
power supply, capacitive HF voltage di-
vider, and temperature probe are available
as optional accessories.
CIRCLE NO. 74 ON READER SERVICE CARD
JERMYN DUAL -TRACE 10-MHZ SCOPE
The dual -trace Scopex Model 4D-10 oscil-
loscope from Jermyn features 10 mV/cm
sensitivity and a dc to 10 -MHz bandwidth.
The all -solid-state circuitry includes MOS
devices. Direct calibration is in V/cm and
,1...
s/cm. A horizontal control incorporates a
x5 expansion function that holds the trace
under observation in the display when acti-
vated. Triggering is regulated by a single
control that governs both level and polar-
ity. In the absence of a trigger signal, the
trace operates in the free -running mode.
All other controls are pushbutton and chop
modes, external trigger, and ac and dc
coupling. Price of the scope is $450.
CIRCLE NO. 75 ON READER SERVICE CARD
HEATH TELEPHONE AMPLIFIER
The Heath kit Model GD-1024 telephone
amplifier kit makes it possible to carry on a
conversation without being tied to the
phone or to conduct "conference" calls
with many individuals participating in one
location. The amplifier operates with virtu-
ally any type of telephone instrument. To
use it, the handset of the telephone instru-
ment is placed on the amplifier's cradle.
The incoming signal is then acoustically
coupled to the amplifier where it under-
goes amplification and is reproduced by
the amplifier's speaker. Volume can be ad-
justed to suit the listening area. Other fea-
tures include all solid-state circuitry for low
no -signal load, 8 -ft (2.44-m) speaker cord
to reduce feedback, and low-cost battery
operation. Mail-order price is $14.95.
CIRCLE NO. 5 ON READER SERVICE CARD
LAFAYETTE DOLBY CASSETTE DECK
Lafayette Radio Electronics' new No.
99-16156W stereo cassette deck features
built-in Dolby noise reduction circuitry. A
,,-e'reen%" t
y"-- r/
,c -
.. ¡
three -position bias switch is provided for
adjusting equalization for standard and
high -output ferric -oxide and chromium -
dioxide tape formulations. Other features
include dual VU meters, slide controls for
microphone and line inputs and line out-
puts, three -digit tape counter with reset
button, memory rewind, and total automa-
tic mechanism shutoff. The deck is capable
of performing sound -with -sound mixing.
Frequency response is 30-12,000 Hz -±3 dB
at 20 dB below 0 VU. S/N is rated at 49 dB
(59 dB with Dolby circuit switched in). Wow
and flutter is 0.12 percent. Retail price is
$239.95.
CIRCLE NO. 76 ON READER SERVICE CARD
LECTROTECH COLOR SIGNAL GENERATOR
The compact Model BG-10 color signal
generator from Lectrotech, Inc., is small
enough to fit into a shirt pocket. Yet, it is a
full -function instrument that provides
crosshatch, dots, single horizontal/vertical
lines, center -screen dot, and three- and
10 -bar color test patterns. The 10 -oz
(283.5-g) instrument employs CMOS LSI
chips for all counting functions for minimal
drain from inexpensive 9 -volt transistor
batteries. The generator's r -f output is on
TV Channel 4 or 5. Overall size is 51/2 in. by 3
in. by 1'/e in. (14 x 7.6 x 2.9 cm). List price is
$89.50.
CIRCLE NO. 77 ON READER SERVICE CARD
INSTANT BREADBOARDING
Instant Instruments, Inc., has developed
Instant Circuit Breadboarding for the de-
sig ner who requires a fast, simple, low-cost
method of transferring his ideas from
paper to wired electronics. This simple
breadboarding method is said to allow in-
stant assembly of a prototype circuit with-
out drilling or insertion of components,
cutting pc boards, or installing jumpers as
required in conventional systems. The de-
signer solders to pre -etched component
pads. Both boards and components are
easily salvaged for reuse. Four basic pat-
terns are available for discrete compo-
nents and IC's. All have pre -punched front
panels. All patterns are solder -plated to
prevent oxidation and to give good
copper -to -solder connection bonds.
Prices range from $2 to $8.60.
CIRCLE NO. 78 ON READER SERVICE CARD
POPULAR ELECTRONICS
AmericanRadioHistory.Com
RK TE
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Enclosed is $ Ship ppd. E Ship C.O.D. Please send ' Mark Ten B assem-
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NOVEMBER 1974 CIRCLE NO. 12 ON READERS SERVICE CARD 15
AmericanRadioHistory.Com
Incomparable!
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CIRCLE
1ti444 I .
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SAE, Inc., Dept. PE 11/74
P.O. Box 60271, Terminal Annex,
Los Angeles, California 90060
Gentlemen:
Please rush free information on the Mark IB Stereo
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return mall.
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NO. 34 ON READERS SERVICE CARD r`
Inside each of our 4 -channel cartridges
AT1,2S AT15S $100.00 AT2OSL $175.00
"$64.95 AT14S
o $75.00
Turks a Dual Magnet stereOicartridge
waiting to please you.
'Our sophisticated four -channel
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All these advantages are as important
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to .CD -4. And they can be achieved
audio technica®
only by paying very close attention to
detail. And using only the best. Like a
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.The results are good for any record ..._
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In Canada: Superior Electronics, Inc.
CIRCLE NO. 3 ON READERS SERVICE CARD
33 Shlawassee Ave., Fairlawn, Ohio 44313
New Literature
ALTEC ENCLOSURE DESIGN MANUAL
"Loudspeaker Enclosures-Their Design
and Use" is a well -illustrated 32 -page pub-
lication for the do-it-yourself audio en-
thusiast. It is a rich source of information to
aid in the design and construction of sys-
tems of predictable and satisfactory per-
formance. Topics include the function of
the enclosure, loudspeaker design theory,
and types of enclosures-from infinite baf-
fles to base reflex enclosures to tuning the
bass reflex port. Details on selection of
materials are abundant-types of board,
acoustic damping material, stiffeners, and
grille material. Other useful information in-
cludes a chart of common sound pressure
levels, frequency ranges of musical in-
struments, and a glossary of audio terms.
Available for $2 from Altec Corp, 1515 S.
Manchester, Anaheim, CA 92803.
ELPA TAPE RECORDER TESTING BOOKLET
"Tape Recorder Clinic Procedures" of-
fered by Elpa Marketing is a 21 -page book-
let that déscribes the step-by-step methods
for conducting a tape -recorder test clinic
using the Ferrograph Ferrotester. The
booklet lists sources from which test tapes
are available and includes a sample Tape
Recorder Clinic Test Report sheet. Ad-
dress: Elpa Marketing Industries, Inc., Tho-
rens & Atlantic Aves., New Hyde Park, NY
11040.
VACTEC PHOTOTRANSISTOR BULLETIN
A bulletin featuring the company's com-
plete line of phototransistors and photo-
Darlingtons is available from Vactec. The
8 -page No. VTTA-1 bulletin describes the
two basic chip sizes and various packaging
configurations. In addition to mechanical
data, it also covers electro -optical
parameters and provides 24 graphs of
characteristics and environmental infor-
mation. Address: Vactec, Inc., 2423 North -
line Industrial Blvd., Maryland Hts., MO
63043.
STANCOR TRANSFORMER CATALOG
The new Stancor Transformer Catalog (No.
407) available from Essex Controls, lists
1600 standard transformers and gives full
technical data, mounting dimensions, and
other specifications on the company's
complete line of audio and power trans-
formers and chokes and inductors. Ad-
dress: Essex Intl., Inc., Controls Div., Stan-
cor Prods., 3501 W. Addison St., Chicago,
IL 60618.
16 POPULAR ELECTRONICS
AmericanRadioHistory.Com
Hobby Scene
Voltage Warning Device
Q.l would like some type of warning
device that will alert me in the event
the dc voltage from my bench power
supply exceeds some predetermined
level. I am looking for sómething sim-
ple that can be put together quickly.
A. The circuit shown here is a zéner-
controlled relay. Select the zener
diode for the maximum voltage you
want from your power supply. Then
use a relay whose coil current is simi-
lar to the zener current of the diode.
When the voltage is below the zener
point, nothing happens. But when the
voltage exceeds the zener diode's
breakdown voltage, the relay will
energize and trigger on the external
alarm connected across the relay's
contacts. The relay will remain on for
all voltages above the zener point, and
will immediately drop out at voltages
below the zener point.
Alarm Delay Circuit
Q. I need a time -delay circuit for my
car that will arm an intruder alarm a
minute or so after I leave the vehicle.
It must work on dc and use a minimum
of parts.
A. The simple timer circuit shown here
should suit your needs. When the
.--F V
/M
/00/ 1FT
2711
NOVEMBER 1974
switch is closed and power is applied
to the system, the capacitor starts to
charge through'the 1-megohm resis-
tor. When the voltage at the emitter of
the UJT reaches the firing potential of
the UJT used, a positive spike will ap-
pear at the gate of the SCR, at which
point the SCR fires. Because the cir-
cuit employs only dc voltages, the
SCR will remain conducting until the
power switch is opened.
Electronic Door Bell
Q. I have repaired my front doorbell
so many times that I'm getting fed up
with it. Isn't there some simple elec-
tronic substitute for the mechanical
buzzer?
A. There are many oscillator circuits
that will deliver a pleasant sounding
20k
(/ND//DUAL TONES)
68k
/K
/0K
TOME
tone when a switch is closed. The one
shown here uses a pair of transistors
and as many switches as you wish.
Each switch is associated with its own
tone -control potentiometer so you
can adjust each one differently. If you
don't have a high -impedance speaker,
try an ordinary transistor output trans-
former and speaker. Any general-
purpose transistors can be used.
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CIRCLE NO. 43 ON READERS SERVICE CARD
Catalog
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CIRCLE NO. 29 ON READERS SERVICE CARD
17
AmericanRadioHistory.Com
ou can se
You can gain exciting new skills
as an electronics troubleshooter in
Bell & Howell Schools' fascinating learn -at-home program that
includes building and experimenting
-;_ ; with the new generation color W.
Simulated N picture/test pattern
,.
i
You may already have some of
the skills you need.
Most of us at one time or another
have put a screwdriver, a pair of pliers or
some other basic tool to work. Fixing a
bicycle wheel, tightening a window latch,
putting up a bookshelf, or what have you.
But here's a thought.
Using these same simple tools as
a starting point, you can develop the
ability to put them to work for you in far
more ways than you ever dreamed of. And
Bell & Howell Schools' fascinating home
learning adventure in electronics will show
you how. These days when it seems like
there's an "electronic everything," it
makes good sense to have occupational
skills in the servicing and repair of such
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equipment. If you're a person who
recognizes a future in this field, Bell & Howell
Schools is ready to help you develop
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become an electronics troubleshooter.
While no assurance of income or
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assure you that no better at-home training
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We have an exciting way for you
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Don't think for a moment that we
want you to spend your off -hours just
reading a bunch of "how-to" books. That
would bore anyone after awhile. What we at
Bell & Howell Schools offer is the modern
way to learn ... a very different approach
from the way you've been used to.
18 POPULAR ELECTRONICS
AmericanRadioHistory.Com
First of all, we believe that when
you're exploring a field as fascinating as
electronics, reading about it is just not
enough. That's why throughout this
learning adventure you'll get lots of "hands
on" experience with some of the latest
electronic training tools available today.
You'll test and experiment with them and
gain exciting new skills all along the way.
Once you've completed this
program a number of directions are open
to you:
1. Use your training to seek out a job in
the electronics industry.
2. Use your training to upgrade your
current job.
3. Use your training as a foundation for
advanced programs in electronics.
4. Use your training in a business of your
own-a few of our graduates are even
doing this now!
No electronics background
necessary.
That's one of the many attractions
of this program. We start you off with the
basics and help you work your way up one
step at a time. As a matter of fact, with your
very first lesson you receive a special Lab
Starter Kit to give you immediate working
experience on equipment as you are picking
up the fundamentals.
It makes the learning process faster and
certainly a lot more interesting.
You'll build and perform exciting
experiments with Bell & Howell's Electro -
Lab " electronics training
system. You build the
Electro -Lab step-by-step,
too. First, the design
console. After you assemble
it, you'll be able to set up
and examine circuits
without having to solder
them in place.
Next, you'll enjoy
building a digital multimeter.
This important instrument
measures voltage, current
and resistance and displays
its findings in big, clear
numbers like on a digital
clock. Far easier to read
than "needle pointer"
meters. Then comes the solid-state
"triggered sweep" oscilloscope which is
similar in principle to the kind used in
hospital operating rooms to monitor
heartbeats. You'll use it to analyze tiny
integrated circuits. The "triggered sweep"
feature locks in signals for easier
observation.
You'll actually build and
work with Bell & Howell's new
generation color TV...
investigating features you've
probably never seen before!
This 25" diagonal color
TV has digital features that are
likely to appear on all TV's of the
future. Features made possible
by the applications
of digital electronics
to home entertainment.
You'll probe into the technology
behind all -electronic tuning and.into the
digital circuitry of channel numbers that
appear big and clear, right on the screen!
You'll also build -in a
remarkable on -the -screen
digital clock, that will flash
the time in hours, minutes
and seconds. Your new skills
will enable you to
program a special auto-
matic channel selector to
skip over "dead" channels
and go directly to the
channels of your choice.
You'll also gain a
better understanding of the
- exceptional color clarity of
Channd numbers that flash on the screen
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On -s reen dgital dock'.
the Black Matrix picture
tube, as well as a working
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Automatic pre-set channel selector Having actually
built and experimented with this TV, you'll
come away equipped with the kinds of
skills that could put you ahead of the field
in electronics know-how.
We try to give more personal
attention than other learn -at-home
programs.
1.
2.
Toll -free phone-in assistance. The
program is designed so that you can
proceed through it smoothly, step-by-
step. However, should you ever run into
a rough spot, we'll be there to help.
Many schóols make you mail in all your
questions. We have a toll -free line you
can call when you have a question that
cant, wait.
In -person "help sessions." These are
held in 50.major cities at various times
throughout the year where you can
talk shop with your instructors and
fellow students.
Why wait?
J
Find out more on how you
can pick up new skills in electronics
troubleshooting as you work with Bell &
Howell's new generation color TV. You've
got the tools to do it!
Mail the postage -paid card today
for full details, free!
Taken for vocational purposes,
this program is approved by the state
approval agency for Veterans Benefits.
It card has been removed, please write to:
An Electronics Home Study School
DEVr7V InSTITUTE OF TECHnOLGGY
on< o< THE
11911F BELLE HOWELL SCHOOLS
4741 Belmont Chicago. IllmO,S 60641
698
'EledtoLab" is a registered trademark of the
Bell & Howell Company.
NOVEMBER 1974 21
AmericanRadioHistory.Com
Monitor 9 or any
channel you choose
CB/PA switch
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[k;"1.
Scan Alert signals you
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9 (can be field -modified
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C. BFa.'28
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AM- CR
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h
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Large
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Transmit
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Illuminated
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Delta Tune helps
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óbra 28
PRODUCT OF DYNASCAN CORPORATION 1801 W. Belle Plaine Chicago, III. 60613
CIRCLE NO. 9 ON READERS SERVICE CARD
NOVEMBER 1974 23
AmericanRadioHistory.Com
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'Bandwidth. If excessive amplifier
power is sometimes a problem, exces-
sive amplifier frequency response
(bandwidth) can be worse. Now and
again a speaker manufacturer will
refer nostalgically to the carefree days
when amplifiers had output trans-
formers, those wonderful low-pass fil-
ters that blocked dc and never let any-
thing much higher in frequency than
the ear could hear (and sometimes not
even that much) get through to the
speakers.
Today it almost seems as if many
transistorized amplifiers have power
responses from dc to practically infin-
ity. Occasionally a defective unit is
found with so much ultrasonic oscilla-
tion running around inside that it al-
most violates the FCC's regulations on
illegal r -f radiation. Ultrasonic stuff,
particularly when it's a constant,
steady-state signal, is extremely hard
on tweeters. At some high frequency
the mass of any tweeter will prevent
it-or at least parts of it-from moving
in response to the signal. This means
that the entire input is converted into
heat; being unable to move, the voice
coil doesn't even have the benefit of
the circulating currents of cooling air
that are set up to some extent during
normal operation. Recently, I heard of
a case in which an amplifier so af-
flicted, when hooked up to speakers of
extremely high power -handling capa-
bility, wiped out all the tweeters before
the music even had a chance to start.
The preventive measure you should
take here-and I've been observing it
ever since the big, wide -bandwidth
amplifiers started to arrive-is to con-
nect up the oscilloscope before you
connect up'the speakers. This will en-
able one to check for ultrasonic out-
put, and also to inspect any low -
frequency turn -on pulses. It's best to
have the rest of the system hooked up
too, since certain combinations of
components seem occasionally able
to set up oscillations that other com-
binations avoid.
Most woofers today are quite sturdy,
physically and electronically. You've
got to be in a position to deliver really
brutal amounts of power to them be-
fore they'll sustain much damage.
Still, this is a possibility that must be
considered. I have not heard lately of
any woofers being hurt by record
warps and such perturbations, al-
though the amount of subsonic
energy they can generate is some-
times startling. But amplifier mis-
behavior is another subject.
Any decent amplifier should be sta-
ble within the limits of its power -
output capabilities, and even beyond
them. And yet stories persist about
certain designs that are believed to
produce horrendous, speaker -des-
troying pulses of subsonic energy
when overdriven, presented with an
unfortunate type of speaker load, or
otherwise mistreated. True enough,
some early amplifiers were subsonic -
ally unstable, and probably the re-
membrance of them feeds the fires of
suspicion about modern units. Fur-
thermore, there are undoubtedly
numerous cases of amplifier defects
that have caused strange, unpredicta-
ble signals to appear at the outputs.
But from what I've been able to learn,
no such misbehavior can clearly be
attributed to any of the modern, popu-
lar models. Speakers are returned to
their manufacturers daily with the
woofer voice coils torn out by the
roots, among other sorts of mayhem.
But it's rarely possible to tell whether
the blame lies with the amplifier or the
user.
Needless to say, an amplifier would
have to be a big one to destroy a
woofer in such dramatic fashion.
Cautionary notes are always in order
with high -power amplifiers. Whether
he suspects trouble or not, it's proba-
bly a good idea for any owner of one to
spend an evening listening with the
speaker grilles off, just to familiarize
himself with the degrees of excursion
the woofer cones routinely go
through.
Another point worth discussing is
the matter of dc voltages (or dc "off-
sets") that may appear at the output
capacitors. In a paper presented sev-
eral years ago, Kerry Gaulder, who
has served in design and engineering
capacities with several major com-
panies, treated this subject at length.
An amplifier with dc offset will, of
course, produce a constant current
through the woofer voice coil. But this
source of voice -coil heating is rarely of
sufficient magnitude to concern any-
one. What is problematic, according
to Gaulder, is the possibility of seri-
ous woofer -cone offset. In other
words, the dc current displaces the
voice coil in the magnetic gap (either
forward or back, depending on polar-
ity), so that it is approaching the limits
of its excursion in one direction, even
when it's not reproducing any sound
and is presumably at rest.
If this theoretical possibility is true,
acoustic -suspension woofers might
CIRCLE NO. 28 ON READERS SERVICE CARD
24 POPULAR ELECTRONICS
AmericanRadioHistory.Com
be more susceptible to this effect than
others. Whereas other woofers have
relatively springy mechanical suspen-
sions that resist offset, acoustíc-
suspension designs depend largely on
the air cushion within their sealed en-
closures to restore the voice coil to its
proper "rest" position. Slow leaks in
the enclosure could cause air pres-
sures within and without the enclos-
ures to be equalized, after a time, for
any position the woofer cone cares to
assume, and that becomes the new
"rest" position. But theory aside, I
have no in -practice facts to support
such a supposition.
A voice coil offset significantly in the
rearward direction is in danger of
striking the bottom of the magnetic
gap with even moderate low -fre-
quency signals. Aside from the dis-
tortion and noise generated, this may
do no immediate harm. But in time the
edge of the voice -coil former (usually
cardboard) may become flattened or
turned over so that it can no longer
clear the magnetic gap freely. An off-
set in the forward direction may
launch the voice coil out of the gap
entirely when a strong signal comes
along, and a safe return cannot be
guaranteed. Both these mishaps may
also occur when a woofer is over-
driven by a powerful amplifier, but
voice -coil offset greatly increases the
probability.
Intrigued by Gaulder's paper, I man-
aged to dig up a direct -coupled am-
plifier with a relatively high dc offset on
one channel. (Gaulder suggests 25
millivolts as the maximum permissible
value.) After letting it work over an
acoustic -suspension speaker with
some pipe -organ music for about an
hour, I measured the offset as 0.16 volt
across 4 ohms (the dc resistance of
the speaker system). Despite this un-
acceptable voltage I was unable to de-
tect any displacement of the woofer
cone after the ordeal, whiich may
prove something or nothing. My incli-
nation is to defer to Gaulder's greater
experience in this area, and so I sug-
gest you pay some attention to dc
voltages when present. Many am-
plifier manufacturers now routinely
specify permissible offset values, and
others would probably give you the
figures they allow if requested.
TIM. Some investigations are cur-
rently being made into a new type of
amplifier distortion-"new" in the
sense that it hasn't been seriously
studied or quantified up to now. It
goes by the name of transient inter -
modulation distortion or TIM. Its
cause appears to be lateness of the
negative feedback signal in getting
back to its assigned earlier stage of
amplification and engaging properly
the signal being processed. The effect
is too brief to be detected by conven-
tional distortion measuring tech-
niques with steady-state test signals, it
is said. But, in effect, what happens is
that the initial onset of an abrupt new
signal within the amplifier (a transient,
in other words) gets through without
being correctly processed by negative
feedback. This results not only in the
feedback's failing to do its distortion -
compensating job, but also in possible
overload of subsequent amplifier
stages.
I don't understand all the aspects of
TIM, or even whether it is the problem
it's been trumped up to be. But if it is,
indications point to the generation of
large amounts of high -frequency
energy and the existence of frequent
overload conditions within the ampli-
fier. (Perhaps I should point out here
that some amplifiers are considered to
be more subject to TIM than others.)
There's really no reason to suspect
i_
/¡i _:., \
AV"\ 3 .
NOVEMBER 1974
le
tt li .
Íe le
M C' Daily frustrations make
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!dal 1r,A"'1 \'Ail UTAH ELECTRONICS
Huntington, Ind. 46750
CIRCLE NO. 42 ON READERS SERVICE CARD
25
AmericanRadioHistory.Com
that it's directly responsible for any
kind of speaker failure, since its dura-
tion is so brief. However, all the results
are not in as yet. Readers interested in
pursuing the subject further should
consult the papers by Dr. Matti Otala in
past issues of the Journal of the Audio
Engineering Society.
The Stitch in Time. The readiest
protection you can give a speaker
from excesses of the amplifier is a
fuse-preferably a fast -blow instru-
ment fuse of the correct value inserted
in series with the speaker. But what is
the correct value? The individual driv-
ers in a multi -way speaker system are
not likely to have the same power -
hand ling capacity. Nor should they. A
few speaker manufacturers are now
fusing some of the drivers in their sys-
tems individually, which is a great
help. But in all frankness I should men-
tion that I hear frequent complaints
about blown fuses from people who
religiously follow manufacturer's fus-
ing recommendations. Probably the
manufacturers, with worst -case situa-
tions uppermost in their minds, have
tended to be a little conservative. Still,
their advice is the best you can get for
your particular speakers.
For over a year I have used 11/2 -amp
fuses in my speaker lines and have
never (fortunately) lost a speaker. I do
lose fuses however-sometimes as
many as three sets a month, although I
have never blown a fuse on music
signals except on one occasion when I
was asking for it. This is not, I em-
phasize, a recommendation, and if
you blow out a speaker following my
practice you can't sue. But if you have
no idea on how to go about fusing
your speaker, this may be a good way
to start. Pay no attention to the nomi-
nal impedance of your speaker sys-
tem, because it is in most cases "nom -
final," having little or nothing to do
with the impedance over most of its
frequency range.
There are on the market a few elec-
tronic speaker -protection devices that
work very well, if you can accept the
way in which they work. Usually
they're connected in parallel with the
power amplifier, so that they can
sense the amplifier output and limit
the amplifier input when a certain level
is exceeded. Their thresholds are ad-
justable, with very approximate cali-
brations provided. But what they do, in
fact, is convert your 100 -watt amplifier
into a 50 -watt amplifier, or a 10- or
1 -watt amplifier. This is because they
act so fast-faster than a fuse, which
will usually pass high-level signals of a
brief, transient nature. (The compara-
tive slowness of fuses is a controver-
sial issue when speaker safety is con-
sidered, but it definitely makes more
sense musically.)
More sophisticated devices are also
available. Several years ago SAE
began equipping some speakers with
active, transistorized "black boxes"
that electronically disconnected the
amplifier when hostile signals ap-
peared. (This made sense because the
tweeters in these systems were elec-
trostatics and had to be plugged into a
wall socket anyway.)
An elaborate protective mechanism
operating at the amplifier is the
"Dynaguard" circuit built into the
Dynaco Stereo 400 power amp. It is
adjustable to limit the steady-state
output of the amplifier from anything
from 20 to 200 watts per channel in five
steps. But its attack time is slow
enough to permit short, "safe" signal
peaks to get through. Perhaps more
important, its action, which affects
only the signal peaks, does not lop off
the tops and bottoms of waveforms
but merely rounds them, curtailing the
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26
generation of high -frequency distor-
tion products (see Fig. 3). The circuit,
by the way, is rarely obvious to the ear
in operation.
Finally, relays that disconnect the
speakers in the presence of dc or
/
Fig. 3. Lower waveform shows effect
of Dynaguard action on sine wave
and lack of high -order harmonics.
strong subsonic signals are being in-
corporated in some amplifiers now.
Basically they function to prevent
"thumps" 'and other noises from the
speakers when the equipment is
turned on, but they will also serve in a
protective capacity, blocking other
hazardous signals that might be gen-
erated any time during operation.
Small Comforts. Articles on
speaker failure always risk stirring up
a lot of anxiety that is frequently un-
justified. Speaker systems are rugged
devices, and have to be. It is under-
stood that they'll be used hard by any-
one enthusiastic about music listen-
ing, and thus they're generally de-
signed to hold' together under any
drive conditions capable of producing
an undistorted, listenable output. If in
spite of this they begin failing chroni-
cally, then manufacturers have to
begin considering every possibility,
since consumers are frequently not
competent to diagnose what went
wrong, and sometimes their com-
plaint reports are not honest for fear of
falling outside warranty terms. This is
why the list of potential hazards has
grown so long.
This discussion concentrates on the
relatively obscure hazards-the ones
that can't readily be heard or other-
wise detected, and which therefore
can't be prevented with a little bit of
common sense. It's possible, even
likely, that not one in a thousand of
you will ever encounter a single one of
them. But if someone, somewhere is
helped by the above to discover a
problem in time, or tipped off as to the
cause of a mishap that has already oc-
curred, then perhaps the telling of this
grisly tale is worthwhile.
POPULAR ELECTRONICS
AmericanRadioHistory.Com
e IG LIGHTS
Computer Pen
A new type of data input device that utilizes a special
ballpoint pen and recognition circuitry that immediately
translates hand -printed data into computer language
has been announced by the Stanford Research Insti-
tute. The Alphabec-70 system, developed at SRI, is
being introduced by Xebec Systems, a California com-
pany in computer peripheral equipment. Using the
Alphabet -70, it will be possible to instantaneously enter
hand -printed data into a processing system. In remote
locations, the data can be recorded for later transmis-
sion to the data processing center.... The first
Alphabet -70 system will have a 16 -character capability
(I O digits and six control characters). A company
spokesman estimates that the system will replace many
of the 700,000 or so keyboard entry devices now in use.
The pen system eliminates keyboard -based procedures
in data entry-and with them, document re -transcrip-
tion, a source of human error, delay, and expense. It is
expected to expedite field data collection in such appli-
cations as utility meter reading and sales order entry by
routemen. The system is also applicable to banking,
telephone -call logging, inventory control, and industrial
data collection.
Purchase Only 53% of TV Receiver Cost
According to a study released by MIT, the purchase
price of a color TV receiver accounts for only 53 percent
of the total amount spent on the receiver during its
useful life. Servicing accounts for 35 percent, and elec-
trical power required for the receiver's operation claims
12 percent over the estimated 10 -year lifetime of the
receiver. "This means that the owner of a $400 color TV
[receiver] can expect to spend another $400 during its
usable life," according to the study. These figures do
not take into consideration future inflation; so, the total
cost of ownership could go progressively higher....The
purpose of the study was to "examine alternatives for
increasing appliance service productivity in the context
of what the consumer pays for a product during its usa-
ble life." The study notes a substantial increase in prod-
uct reliability as evidenced by a 50 -percent decline in
the need for color receiver- servicing during the last
eight years. However, service costs have increased so
greatly as to offset what would have been a sharply
reduced life -cycle cost.
UA Releases 10 -in. 78 -rpm Disc
In keeping with the present popularity of "nostalgia,"
United Artists has released a 78 -rpm disc containing two
selections from its Golden Age of the Ilollywood Musical
album. "We're in the Money" and "Lullaby of Broadway"
(both from Bushy Berkeley film musicals of the 1930's)
were pressed on a 10 -in. mold and fitted with record
labels that mirror the typographic and design style of the
period. This necessitated the retooling of UA's pressing
plant since 10 -in., 78 -rpm discs had not been pressed
there in more than a decade and there was only one
10 -in. die to be found in all of Los Angeles. ...The
reported vinyl shortage did not hamper progress on the
project because 78 -rpm discs are composed mainly of
shellac and filler materials.
NOVEMBER 1974
Good time
coprule.
Saving fleeting moments requires a quality tape
recorder. But, just as a camera can be no better
than its lens, tapes can be no better than the micro-
phone. Whether it costs $200, $500-even $1,000-
a tape recorder can be significantly improved by
the addition of a Shure unidirectional microphone
-a mike that can be'"aimed" so that only the tar-
get sounds will be recorded. Microphone misers
who ignore this will never hear the true sound of
recorded musilc lessons, parties, classes, speech
therapy, sound movies
and rehearsals. With
Shure microphones,
creating tomorrow's trea-
l - sures is today's pleasure.
Shure Brothers Inc.
222 Hartrey Ave.,
Evanston, III. 60204
In Canada: A. C. Simmonds
& Sons Limited
SHUFtE °
Manufacturers of high fidelity components, microphones, sound systems and related circuitry.
CIRCLE NO. 46 ON READERS SERVICE CARD
AmericanRadioHistory.Com
Why a Sylvania home training program may be
your best investment
for a rewarding
career in electronics
r G
-----. ,
,.
: yL
.+
\"1."7.1,
'
. b ...i...
; _ ed"" ,
_
:;.::. r tA.,.
28 POPULAR ELECTRONICS
AmericanRadioHistory.Com
LEADER IN ELECTRONICS
I TRAINING
Over the years, Sylvania Resident
Schools have trained thousands of
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While you hold your present job.
Remember, this training is designed
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you the background you need to land
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6 HANDS-ON TRAINING
To give practical application to your
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included in many programs. In
Sylvania's Master TV/Radio Servicing
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In tie Mas-er TV/Radio Servicing Program,
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NOVEMBER 1974 CIRCLE NO. 17 ON READERS SERVICE CARD 31
AmericanRadioHistory.Com
Popular Electronics
NOVEMBER 1974
e
EVER since we published construc-
tion plans for the world's first hob-
byistlexperimenter's laser in De
cember of 1969. POPULAR ELEC.
TRONiCS-has kept readers abreast
.oflaserdPvelopments.Forexample.
in January 1970. we gave details
on how tó use the laser for making
three-dimensional holograms.
Then, in May 1970. we. published
plans for assembling a laser voice
communicator (which, incidentally,
was featured for several weeks in
the Smithsonian -Institution).
Now. -we have another break-
through -plans for building the
world's first experimenter's laser
video (TV) system for a moderate
$150. (The TV camera and receiver -
are extra items.)
-T HE POPULAR ELECTRONICS
laser TV system gives you an
advance look at a commLnication
system of the'future. There are two
key-devices'in the system. -One is
the. composite laser tube/video
modulator "transmitter" -that works
iR conjunction -With a low-cost TV
camera. The other is the
détector/r-f modulator "receiver'°
that feeds aq ordinary TV receiver.
(See box on Class -1 requirements.)
r,
n.onLi.M
The helium -neon laser tube used
in- the _system employs the latest
aluminum cathode, -design. The
tube' is used in conjunction with
solid-state modulation and detec=
lion circuits. ' With. the. laser TV system, you
can expect a range up to 50 ft with-
. out special optics. For extended
range, you can use a telescope
and/or a converging lens. More
about range later in the article.
Overall System.. The ,block dia-
gram of the overall laser TV system
is shown in Fig. 1. The video (or
audio, not .both simultaneously)
output signal from the TV camera is
typically on the order of 1' volt
.peak-to-peak.This-signal is fed to
the laser- modulator, which is, de-
signed to provide- a gain of 2
mA/volt. Hence;'the'i-volt p -p video
output signal from' the camera,
after passing through the mod-
ulator,'is converted to a 2-mA p -p
. signal that current -drives the laser
tube. . ' - - . .
Thé gain of, the laser -tube is
about 0.1 mW/mA, while the laser
detector -has again of 1.25 mA/mW.
The r -f oscillator in the detector is
tunable over a 60- to 72 -MHz range
to permit the system to operate on
TV channel 3 or channel 4, ..
Whichever is not in use in your
area.
The output o.f the r -f modulator is
an amplitude -modulated (AM)
° signal that is adjustable from 0 to 5
mV rms. This signal can be fed into
an ordinary TV receiver through its
vhf antenna terminals by means of -
300 -ohm twin -lead cable. '
Laser/Modulator Circuit. In the
slaser/modulator power supply,
shown schematically in Fig. 2, TI,
C5 -C8; a-nd D9 -D14 are arranged in
: a voltage doubler configuration
- that serves as the main high -
voltage supply. This supply deliv- -
ers about'1700 volts to the laser -
° tube -Diodes Dl -D8 and capacitors °
C1 -C4 form two more voltage doub -. - d
lers that are "stacked" on top of
the main high -voltage supply for
ionizing the gas in the laser tube.
As soon as ionization is complete,
current starts to flow through the.
laser tube. However, the values of °' I
C1 -C4 are too low to support the -
5-mA tube -current. So,.the starting
voltage collapses and only the
main sustaining voltage remains.. °.
Transformer T2 and its as-
sociated rectifiers (D15 -D18) and.
filter capacitors (C9 -C14) make up a
32 POPULAR ELECTRONICS
AmericanRadioHistory.Com
o
ANOTHER
PE TES3
EXCLUSIVE
BUILD A
Laser
TV
System.
BY GIANCARLO PUNIS
AND JOSEPH O'DONNELL
Now you can
transmit and
receive black and white
TV pictures over
a substantial
distance with a
license -free
laser beam
video link
°
the low -voltage supply that del-4-
ers the +20- and -20' -volt Ines or
'tie low -voltage portions of the
mcd.ilator.
High -impedance amplifier Q/
prearnplifies low-level microphone
signals of about 0.1 volt p -p to the
1-vo t pp level required to drive Q2
to obtain the full 15 -percent mod-
! Llation. (See Fig. 3 for the mod-
. Llator schematic diagram.) The
high-level 1 -volt p -p video input at
-J2 and the collector of Q/ are both
ac -coupled to the .base of Q2 and,
I therefore, to each other. Hence,
Whel using either of the.J1 (audio)
or J2 (video) inputs, it wil t e
necessary to disconnect the un-
used input.-. This is important to
prevent interference between the
.
two signals as well as to prevent
loacingQ1's collector.
Transistors°92-Q4 each provide
some gain at the lower frequencies
and one stage ,each -of high-
trecpency boost, starting at about
253 kHz and ending at about 1 MHz.
The boost characteristics are
achieved by the RC networks used
' as emitter loadsfor the transistors.
In addition, thee are two broadly
traps consisting 2f
C24.1_1/R16 and C25/L2/R22 cen-
tered at160 kHz and 330 kHz.
. -
- 3
z 5
.
he- frequency response of the
laser tube only is -shown in Fic. 4A. -
TI -e strong peak at 170 kHz wciuld.' n: -
cause severe overshoots enticing-.
ing on the fast edges cf TV sync .
pulses or any sharp while-to-blaCk , -
transitions. In addition, the -3 -dB yt°
bandwidth is only 250 kHz. wide,
with correspondingly peor picture
resolutior. So, to smooth out the' -
frequency response and to extend.. -
it beyond 500 kHz, the modulator
combines boast circuitry and traps -
to yield the compensatinc re-
sponse shown in Fig. 4B. Combin-
ing the A and -B response ctives,--
the overall laser tube/-nodulátór -
system has the. frequiency .
sponse characteristic shown
Fig. 4C, w-iich is adequate for most' °
appicationa. -
The frequency-cornoenseted:
signal is coupled to Q5, which acts
as a current source for troth the dc'.
bibs (tri-nned to 5 mA by R33: and-.
the ac signal currents for the laser
tune. Except for a small amount of
current through R27 and R28. the
current sourced by Q5 alsó lows.
th oughQ6 and Q7, ballast resistor - -
R26. and the laser tube. Each rated
at 300 volts, Q6 aid Q7 are cas-
caded to act as one transistor with '- . .
a 500-voll break -down rating. -. .
. " _-33-'
AmericanRadioHistory.Com
MODULATOR
TV
CAMERA
PHOTO-
DETECTOR
TV
RECEIVER
Fig. 1. Block shows
the basic arrangement of
the laser video- link.
Detector Circuit. Phototransistor
Q1 in Fig. 5 is connected as a photo -
diode, providing a 40-µA p -p signal,
depending on the intensity of the laser
beam. This results in a 200 -mV video
signal at the base of Q2.
Transistor Q3 is a Hartley oscillator
stage, whose operating frequency is
determined by L1 (printed on the cir-
cuit board as part of the conductor
pattern), C7, and C8: Capacitor C7 is
adjustable to permit the circuit to op-
erate on either the TV channel 3 or
channel 4 frequency.
TO
LASER
CATHODE
20V
CI-C4.001yF 2KV C5-C84.7yF,450V. C9 CI4.100yF,
R29 -R32 'MEG. ' DI-DI8IN4007 26V
Fig. 2. Half of high -voltage
supply "drops out" when
laser starts. Low -voltage
supply is more conventional I
34
The vhf carrier is ac -coupled to
mixer diode D1 through C6, resulting
in a video -modulated vhf signal of
about 5 mV rms with r -f level control
set for maximum output. The r -f signal
goes directly to the vhf antenna input
terminals through 300 -ohm twin -lead
antenna cable. Note, however, that
when the output of the detector circuit
is connected to the TV receiver's an-
tenna terminals, the regular TV an-
tenna cable must be removed.
Zener diode D2 provides a 3.6 -volt
dc bias supply for Q2 and serves as the
dc supply regulator for the Q3 oscil-
lator circuit.
Assembling the System. Except
for the laser tube, jacks Ji and J2,
transformer Ti, and power switch Si,
all components shown in Figs. 2 and 3
mount on a single printed circuit
board. The actual -size etching and
drilling guide and components
placement diagram for the laser/
modulator system are shown in Fig. 6.
To permit the etching and drilling
guide to be reproduced without re-
duction, it is shown in two parts. The
left edge of the lower portion butts
against the right edge of the upper
portion, with the ground bus (heavy
black areas) aligned.
When wiring the circuit board ac-
cording to the diagram in Fig. 6, take
care to properly orient the compo-
nents. Pay particular attention to elec-
trolytic capacitor polarities, transistor
basing, and T2's lead routing. Bear in
mind that T2 and the laser tube mount
on the foil side of the board. Also, all
resistors (except R26 and R29 -R32)
and L1 and L2 mount on -end. The rest
of the components mount on the
board in the conventional manner.
Note that only C5 -C8 are axial -lead
capacitors, designed to mount flat on
the board, while all other electrolytic
capacitors are upright types.
Potentially lethal voltages are de-
veloped in the laser circuit. Conse-
quently, it is imperative that the entire
assembly be mounted inside a rugged
- preferably metal - enclosure. Use
only nylon screws when mounting
anything inside the enclosure to pre-
vent access to any high -voltage points
in the circuit once the system is as-
sembled. Select an enclosure that is
large enough to accommodate the
laser tube, pc board assembly, and
transformer Ti. Mount closed-circuit
miniature phone jack Ji, BNC jack J2,
and power switch Si on the rear wall
of the enclosure. In another hole .on
this wall should be the three -
conductor power cord, held in place
with a plastic strain relief. (Or line the
hole with a rubber grommet, pass the
line cord through, and tie a knot in the
cord.)
The exit hole for the laser beam
must be drilled through the
enclosure's front wall, directly in line
with the beam's travel. Use a 1/4 -in.
(6.35 -mm) diameter drill bit. If possi-
ble, mount a tubular flange with a fer-
rous outer ring as a bezel over the
hole. The ferrous ring is a conveni-
ence feature that supports the various
lenses that come mounted in circular
magnets in the event you decide to
perform other experiments using the
laser.
Solder push -on connectors to one
end of a red and a black 3 -in. (7.72 -cm)
or less pieces of 5 -kV test -lead cable.
Shrink tubing over the connections.
Then solder the free end of the red
cable to point A and the black cable to
point C on the foil side of the pc board.
Drill 1/8 -in. (3.27 -mm) holes through
the donuts marked X on the pc board.
Mount a tube mounting clamp at each
hole location. Orient the laser tube so
that its pin -connector end is toward T2
and the anode pin on the narrow neck
points toward the red cable. Set the
tube down in the clamps and anchor it
in place with rubber hold downs. Cau-
tion: Do not mount or handle the laser
tube by its narrow necks.
Slip the red cable connector onto
the anode pin of the laser tube. Then
locate the cathode pin on the opposite
side of the tube from the anode pin,
and slip the black cable's connector
onto it.
Solder 10 -in. (25.4 -cm) long pieces
of hookup wire, preferably color
coded for easy identification, to the
remaining holes in the pc board. Slip
1 -in. (2.54 -cm) long pieces of heat -
shrinkable tubing over the wires con-
nected to the Ti secondary points.
Then mount the board in the enclo-
sure with nylon screws and insulated
spacers.
Mount Tl on the floor of the enclo-
sure. Then locate the leads with the
shrinkable tubing on them. Route
these leads along the component side
of the board, and connect and solder
them to Ti's secondary winding,
trimming as necessary. Shrink the tub-
ing tightly over the connections.
Complete the wiring, referring to Figs.
2, 3, and 6.
Assembling the detector is a very
simple, straightforward process. Ex-
cept for phototransistor Q1 (Fig. 5),
output connector, and power switch,
POPULAR ELECTRONICS
AmericanRadioHistory.Com
+20V
- RI
JI
AUDIO
J2
VIDEO
R4 2 R8
1220K y¿ 8.8K.- 015 CI6 39K '
' IpF ' IpF
cl +eJ _ \l+
2N4124
. .`
22pF \ 1C20
R2 R5
82K 39011
R12 R14
39K 12K
02 1 T ILj 03
2N4123 1 t\ t 2N4123
200pF\íC211 - 1 100pF
R7 RIO
8.2K IK
RII
8.2K IK
LI
Q IDmN
C2410opF
IC23
k
13.3K_
R13 x RI6
1; .36
72
-20V
TO LASER ANODE -+J_ R26
33K
627
180K
LASER/MODULATOR PARTS LIST
Cl -C4 -0.001-2.F, 2 -kV ceramic disc
capacitor º
C5 -C8 -4.7-µF, 450 -volt axial -led elec-
trolytic capacitor '
C9 -C14 -100-1.¿F, 25 -volt upright elect
trolytic capacitor
C15 -C18 -1-µF, 50 -volt uptight elí ctroly1
tic capacitor
C19 -0.15-µF disc capacitor
C20-22-1hF, 10 -volt upright electrolytié
capacitor
C21, C22-200-pF, 100 -volt disc capacitor
C23. C24-100-pF, 100 -volt -disc capacitor_
C25-25-pF, 100 -volt disc capacitor
Dl-D18-1000-PIV, 1-A rectifier
(1N4007 or similar) _
J1-Miniature shorting-type_phone jack -
J2-BNC jack
LI, L2-10-mH choke
Q1 -2N4124 transistor
Q2 -Q4 -2N4123 transistor
Q5 -2N3906 transistor
Q6, Q7-MPSU-60 transistor (Motorola)
R1 -220,000 -ohm
R2 -82,000 -ohm
R3 -10,000 -ohm
R4, R17, R20 -6800 -ohm
R5 -390 -ohm
R6, R12, R18=39,000 -ohm
R7, Rll, R22 -43200 -ohm
R8, R13, R16 -3300 -ohm
, R9 -15,000 -ohm All resistors
R10, R15,,R21-4000-ohm 1V2-wdtt, 10%
R14 -12,000 -ohm _
R19 -2200 -ohm
R23, R24 -56,000 -ohm
R25 -3900 -ohm I
R27, R28 -180,000 -ohm
R29-R32-1-megohm
R26 -33,000 -ohm, 2 -watt resistor
R33 -10,000 -ohm upright pc trimmer
potentiometer
Sl-Spst switch
T1 -640 -volt, 25-mA power transformer
T2-Dtial 15 -volt, 25-mA power trans-
former
Misc.-Metal enclosure; printed circuit
board; laser tube No. PE719; mounting
clamps for laser tube mountings 5 -kV
test -lead -cable; three -conductor line
cord; pin connectors (2) for anode and
cathode cables; heat -shrinkable tubing;
rubber grommet or plastic cable
clamp/sttain_ relief; nylon mounting
hardware and insulated spacers;
1000-ohm, 1/2 -watt resistor (for trans- l
mitter checkout); hookup wire; solder;
etc. ,
Note: The following items are available 1.
from Meti`ologic Instruments, Int., 143 -
Harding Ave., Bellmawr, NJ 08030:
No. PE719 laser tube ($96); No. PE640
640 -volt power transformer ($7); No.
PE101 etched and drilled transmitter pc
board ($6); No. PE201 etched and dril-
led detector/ modulator pc board ($3);
No. PE669 complete kit of transmitter
parts. including laser tube, pc board,
transformers, metal housing, etc.
($124.50); No. PE301 complete kit of
detector/ -modulator parts. including
housing ($25);. No. PE500 complete kits
of transmitter and detector/modulator '
parts (not including TV camera) ($148).
All prices postpaid. Canadian readers
can order from Merlon Scientific; Ltd.,
825 Lake Shore Rd., Port Credit, On-
tario, Canada -
R18
39K
Fig. 3. Frequency response of video amplifier is "tailored" to i)nTrrave
laser tube's respvnse.Resulting video Modulates laser beam
4
everything mounts on a small pc
board. The actual -size etching and
drilling guide and components
placement diagram for the detector
are shown in Fig. 7. Note that coil L1 is
part of the printed wiring.
The on -board components mount in
the conventional manner. Just be sure
to properly polarize the electrolytic
capacitors and transistors. Transistor
Q1 mounts in a hole on one wall of the
metal enclosure, its lens "looking" to
R20
6.0K
04
2N4123-
200pF
R21
IK
L2
6 _10mN
a C2pF
1C22 -7
RI9 5822
2.2K 18.2K
Q7 '
MPSU-60 j_
. 828 -
1806 =s
R24 R26
56K _ 3.9K
- 06
2N3908
R33
10K
}R23
136K
06
MPSU-60
CAUTION
Never look into the laser
beam proper or directly into
its reflection.
-10dB
-13d8.
+16dB
+1.0dB
ode
-1Ód8
008
006. .1mW/mA
-- ' =--a
(A)LASER TUBE
1 r
i.
" 0d6.2mA/V
(B) MODULATOR
008..ImV/V
- 50 (C)=OVERALL - 1 ÓNN:kBi SOÓ Nz =
Fig. 4. Response curvés "of
laser tube (A)`and modulator
(B) combine to provideflat
overall systéin. response 1(C).
the outside world. The phototransistor
can be held in place with a bead of
clear epoxy or plastic glue.
Install the battery on the floor of the
enclosure, under the pc board assem-
bly, in a battery clip. And power switch
NOVEMBER 1974 35
AmericanRadioHistory.Com
CI -1-1_ _,j_ C2
IOpF 005VF R RS i8
T 10K DOK
01
MRD3050
\ . R 22K
C3
10pF
02
2N4124
C4 21_50pF
R4
10K
C5 02
50YF 3.6V
RIO 61
1320.0. 9V
30011. LINE
Qe C7
5pF , 5-30pF
C10 _ CII C12
R8 , ".005pr 1 10pF + .005pF
33011 y
DETECTOR/R=F MODULATOR PARTS LIST
B1 -9 -volt battery
Cl, C3, C11 -10-µF, 10 -volt electrolytic .
capacitor
C2, C10, £12, C13 -0.005-µF disc
capacitor
C4, C5 -50-µF 10 -volt, electrolytic
capacitor
C6-7.5-pF silver -mica capacitor
C7-5-30-pF miniature ceramic trimmer
capacitor
C8-5-pF silver -mica capacitor
C9-68=pF silver -mica capacitor ' "
D1 -1N295 diode
D2 -3.6 -volt zener diode (1N747 or simi-
lar)
LI-R-f coil (etched oh pc board)
L2 -620-0H choke
QI-MRD-3050 phototransistor (Moto-
rola)
Fig. 5. Photodetector modulates oscillator
that goes via 300 -ohm line to television rec
S1 and the output cable connector
mount on the rear wall of the enclo-
sure.
System Checkout. Before applying
any power to the laser/modulator,
double check all components for
proper installation. Check particularly
for cold solder joints and solder
bridges. If everything checks out okay,
disconnect the primary of Ti, Q6, and
the laser tube from the circuit.
Temporarily connect a 1000 -ohm,
1/2 -watt resistor between Q5's collec-
tor and the -20 -volt bus. Turn on the
power. Now, using a high -impedance
multimeter (a 20,000-ohms/volt VOM
will do), check to verify that +20 and
-20 volts dc is available from the
power supply. Because of the tempo-
rary collector load, Q5's collector will
be at about -15 volts. Adjust R33 for a
reading of exactly 5 volts across the
temporarily installed 1000 -ohm resis-
0,-2N4124 transistor
Q3 -2N3692 transistor
RI, R3, R4 -10,000 -ohm
R2, R9 -22,000 -ohm
R5 -270 -ohm
R6 -100,000 -ohm
R8 -330 -ohm
R10 -820 -ohm
R7 -250 -ohm, vertical pc -type trimmer
potentiometer
SI- Spst switch (optional)
Misc.-Chassis box; printed -circuit
board; battery clip; output cable con-
nector (optional); 300 -ohm twin -lead
cable; hookup wire; spacers (2); hard-
ware; etc.
(Note: For kit information, see Laser/
Modulator Parts List.)
All resistors
1/2 -watt, 10%
on channel 3 or 4 to generate signal
eiver's antenna terminals.
tor. Alternatively, insert a milliamme-
ter in series with the resistor and ad-
just R33 for a reading of exactly 5 mA.
Turn off the power and disconnect the
line cord from the ac receptacle.
Wire Ti into the circuit. Before ap-
plying power, remember that poten-
tially lethal voltages are present at the
negative end of C5 and the cathode
(black) lead. Keep the latter well away
from ground and the low -voltage cir-
cuits. The starting voltage at the top of
C3 can be checked, but the meter has
a loading effect on the circuit. So, do
not expect to read more than about 3.5
kV when making measurements on
the 5 -kV range with a 20,000 -ohms/
volt meter. Turn off the power, and re-
move the plug from the ac receptacle.
After power is removed, do not touch
any part of the circuit for about
five minutes until the high -voltage
charges on the capacitors dissipate.
When the circuit is safe to handle
again, remove the temporary resistor
from Q5's collector circuit and recon-
nect Q6. Connect the anode lead to
the tube and a 0-10-mA meter in series
with the tube's cathode pin and the
cathode (black) lead. Make certain
that the milliammeter and its leads are
well separated from ground and the
low -voltage circuits.
Plug in the line cord and turn on the
power. After a short lag, the gas in the
laser tube should ionize and glow
CLASS -1 TV DEVICES
There has recently been a proliferation of
electronic games designed to be used with
a conventional TV receiver. These so-
called "Class -1" devices apply a mod-
ulated low-level r -f carrier signal directly
to the receiver's antenna terminals. Be-
cause they might produce interference, the
FCC has placed restrictions on the man-
ufacture, sale, and use of Class -I devices,
of which the laser detector/r-f modulator
in this article is one.
Class -1 TV device requirements are:
I. They must operate on a channel allo-
cated for vhf or uhf broadcast TV.
2. They "must transmit the r -f signal to
the TV receiver by wire or cable.
3. The r -f output level must be less than
6 mV rms into a 300 -ohm output.
4. A transfer switch with 60 dB of isola-
tion must be used for switching the an-
tenna terminals between the TV antenna
and the Class -I device.
5. The peak envelope power of any
spurious emission at frequencies 3 MHz
or more from either edge of the standard
TV channel being used must be 30 dB or
more below the peak envelope power of
the in -band signal.
6. Radiated EMI from the device must
be less than 15 µV/meter at 2.6 ft. (0.79 m)
from the detector modulator.
7. The device must be formally type ap-
proved by the FCC. In the case of a kit -
form Class -I device, only the manufac-
turer of the kit is required to obtain type
approval.
The above list of regulations applies
only to the detector/r-f modulator portion
of the laser TV system. No specific re-
strictions are placed on the laser transmit-
ter. With regard to the isolating switch, the
laser TV system has none, but removing
the TV receiver's antenna will satisfy the
requirement. (Bear in mind that it is illegal
to have the detector's output cable and the
TV antenna hooked up to the TV receiver
at the same time.)
The detector/r-f modulator has been
type approved by the FCC. However, it is
strongly urged that if you build your own
instead of buying the kit from Metrologic,
you faithfully follow the pc layout and as-
sembly instructions presented in this arti-
cle.
36 POPULAR ELECTRONICS
AmericanRadioHistory.Com
ñ2á
06
E B C
07
M
C B E
-R33- R28- -R27-1
1
06 o
C B E R25 f 6 R}4 ` T
/1'¿ C9
1/20 + C ' 14-
C19 p! R18I C18 RI4 RI2 C17 -R9 CI6r 01B A
L2, C < + t 1 C i i + 1 6 E C20
C23 043 i1 03B t ! 1 CO
r E f T C23 E -C21-:2:E8 CI8 t t i+
R22 C22 RI9 RI7 C24
, f 4 4 1 i t R3 RII RI0 8 I7 R R3
R21 RI6 RIS - \\4 1
. = R2
R24
t ti
LASER
ANODE
414C .. 00
-C4--
DB * 1' T
O * D7 11 i 03
T D6 T
D5 *
-RI JI(AUDIO)
ONO 1 J2 (VIDEO)
XO
LASER
CATHODE
1 -C3-
D4 * 3:
* D2
?1
DI *
-"a-C2- 1 -CI-;
-0I6y 41-0I6-76
0-018- 4r -D17-5
AC LINE
TI PRIMARY
Fig. 6. Actual -size
etching and drilling guide
for power supply and
n odulator is shown in two
parts (center). The
component -placement guides
are shown above (top)
and below (left) their
respective etching guides.
NOVEMBER 1974 37
AmericanRadioHistory.Com
g
p º
.. .o
.
.,---+-
s-.
+
t1
Fig. 7. Actual -size etching
guide for detectorhnodu.lator
(bottom) features printed
r -f oscillator coil. Component -
placement guide is at left.
orange. (Caution: Never look into the
laser beam or directly into the re-
flected beam.) The milliammeter at
this time should indicate a 5-mA cur-
rent flow. If necessary, touch up the
setting of R33 to obtain a 5-mA read-
ing. Then turn off the power and re-
move the line cord from the ac line.
Again, do not touch the assembly until
the high -voltage charges have bled off
the electrolytic capacitors. Then re-
move the milliammeter and reconnect
the black cable to the cathode pin on
the laser tube.
Reapply power to the system. Now,
exercising extreme caution, measure
the collector -emitter voltages on Q6
and Q7. Both transistors should have
approximately the same voltage drop.
An unequal drop indicates that some-
thing is wrong, meaning that you will
have to troubleshoot the circuit.
Since the detector employs only a
low -voltage battery supply, it is safer
to work on than the laser/modulator.
The emitter of Q1 should be at 0 volt
with no light entering the phototran-
sistor through its lens. With the laser
beam impinging on the sensitive sur-
face of Q1, the emitter will be at about
2 volts. (Note: A 20,000-ohms/volt
meter will load this down to about 1.6
volts.)
Connect the r -f output line to the
antenna terminals of a conventional
TV receiver, after first removing the TV
antenna cable. Adjust C7 for operation
on either channel 3 or channel 4,
whichever is not in use in your area.
Now, modulating the laser with a TV
camera, an oscilloscope should reveal
the composite video signal at the emit-
ter of Q1 at a level of about 220 mV p -p.
(Almost any type of oscilloscope can
be used here.) The waveform at the
.cathode of D1 will be the video -
modulated r -f signal operating at
about a 5 -mV p -p level. It may be
necessary to adjust R6 to obtain the
correct signal level.
If you do not have access to a scope,
set potentiometer R7 to the middle of
its range. Set the TV receiver to the
unused channel 3 or 4. Very slowly
adjust C7 for the clearest, sharpest
picture on the screen of the TV re-
ceiver, while video -modulating the
laser. Then adjust pot R7, and the TV
receiver's brightness and contrast
controls for the best picture quality.
Also, if the TV camera does not have a
wide agc light range, its lens should be
adjusted as well for best picture.
Setup and Use. In setting up the
laser TV system, bear in mind that
adequate light must be on the subject
to be televised. Avoid subjects (pic-
tures) that have very bright and very
dark contrasts close to each other.
Focus the camera carefully, and select
the best lens opening for the subject
to be televised.
When mounting the laser/mod-
ulator and receiver, use solid supports
to obviate vibrations and shifts that
might cause the laser beam to miss the
phototransistor in the detector and re-
sult in transmission drop -outs.
The uncollimated beam from the
laser has a 1-milliradian divergence
characteristic that causes the spot to
spread to about 1 meter in diameter at
1000 meters. So, if you plan on long-
distance transmission of the laser
beam, you must use collimation to
keep the beam as narrow as possible.
The collimator is simply a telescope
used backwards, with the laser beam
fed into the eye -piece and exiting
through the large end of the tele-
scope. You can use either a reflecting
or a refracting telescope.
The greater the power of the tele-
scope used, the greater the range you
can expect and the tighter the laser
beam. However, with increasing
range, optical alignment becomes a
critical factor. So use a solid mount for
the telescope.
Range can also be increased with a
light -gathering lens at the detector
end. This is comparable to using a
high -gain antenna for radio waves.
You can buy lightweight plastic Fres-
nel lenses measuring up to 11 in.
(27.94 cm) square at very reasonable
prices. Such lenses make excellent
light gatherers. They must be focused
on the sensitive surface of the photo -
transistor in the detector.
Long-distance alignment can be
simplified in several ways. Use a rigid
mounting system and some form of
vernier positioner (for fine adjust-
ment) for aiming the laser. Perform the
alighment at night when the bright red
laser beam is easier to see. For night
setups, a bicycle safety reflector will
prove useful in following the beam to
the detector target.
38
1
POPULAR ELECTRONICS
AmericanRadioHistory.Com
'i .
/>d
o/ 0 HOW THE
_.
4
/(`aA NEW FT
HI-H RULES
AFFECT YOU!
EFFECTIVE November 4, 1974,
new rules governing the disclo-
sure of the output power of audio am-
plifiers and receivers go into effect.
The new rules were promulgated by
the Federal Trade Commission after
several years of study. They follow a
long period of advertising abuse by
some segments of the electronic
home -entertainment industry.
Well-known "low -fi" productsclaim-
ing output power capabilities of as
much as 100 watts "instantaneous
peak power (IPP)" have been mea-
sured by reputable laboratories and
have consistently produced no more
than a few watts of output power per
channel at best. Meaningless terms
such as IPP, peak power, peak music
power, and dynamic music power-if
they are to be used in the future at
all-will have to be given less typo-
graphical prominence in all advertis-
ing media.
Still Room for Ambiguities. Will
the FTC rule end the confusion about
NOVEMBER 1974
1.0
0.8
z o
I - cc o y 0.6
o V z o
cr i 0.4
0.2
BY LEONARD FELDMAN
ALL AMPL FIERS REFERENCED TO
8 -OHM LOADS
- .~01. r.mIM ..m1M1
I
A
10 20 30 40 50
POWER OUTPUT/CHANNEL (WATTS)
Fig. 1. When all three amplifiers are measured the
same way, "lower spec" amplifier A turns out
to be.the highest powered unit among the three.
60 70
39
AmericanRadioHistory.Com
power ratings in the minds of all con-
sumers? Unfortunately, the answer is
a resounding "No!" While the rule
goes a long way towards enforcing
honesty in audio equipment advertis-
ing, adherence to its requirements will
not, in and of itself, make everyone's
power specifications read like
everyone else's. The consumer can
still be thoroughly confused when
reading specification sheets describ-
ing competitive amplifiers and receiv-
ers. Here is why confusion can arise:
Henceforth, manufacturers will be
required to state continuous output
power delivered by their products into
a specified impedance, at a specified
harmonic distortion, and over a
specified power bandwidth. The
power specified in this manner must
be delivered by the amplifier or re-
ceiver when all its channels are driven
simultaneously. For a stereo receiver
or amplifier, this means that both
channels must be going at the same
time, while in a 4 -channel setup, all
four amplifier channels must deliver
the rated power to all four loads at the
same time.
Let us consider the following sets of
competitive specifications, all of
which would comply with the "letter of
the law":
AMPLIFIER A: 50 W/channel output
power into 8 ohms at 0.3 percent har-
monic distortion from 20 Hz to 20,000
Hz.
AMPLIFIER B: 60 W/channel into 4
ohms at 0.5 percent harmonic distor-
tion from 60 Hz to 400 Hz.
AMPLIFIER C: 65 W/channel into 4
ohms at 1.0 percent harmonic distor-
tion from 60 Hz to 4000 Hz.
Reading these three descriptions,
the uninitiated consumer might con-
clude that Amplifier C has the greatest
output power capability. He would be
wrong. Nearly all solid-state amplifiers
produce their greatest output power
3.
z 03 '
0 p.
5 2.
21 0 z CC I.
4 = O.
levels when connected to 4 -ohm
speaker loads. Connected to more
popular 8 -ohm speaker system, Amp-
lifierC might well produce less than 50
watts.
Notice, too, that the rated distortion
of Amplifier C is 1.0 percent. How
much less power would it be able to
deliver-even into its 4 -ohm specified
loads-if distortion were limited to 0.5
or 0.3 percent, as in the cases of Am-
plifiers B and A? For that matter, we
have no way of knowing from the fig-
ures given whether or not the distor-
tion level will ever go down to the
0.3 -percent level. Perhaps 1.0 percent
is the best Amplifier C can do even at
low output power levels.
The new FTC rule merely requires
that the amplifier be able to deliver its
specified power at a harmonic distor-
tion that does not exceed the pub-
lished figure. Doing some hypotheti-
cal calculation based on typical
measurements observed with "real"
amplifiers, Fig. 1 plots power versus
distortion curves for our three ficti-
tious amplifiers. The parameters were
changed so that each amplifier was
operated into 8 -ohm loads, and all
three were permitted to reach a distor-
tion level of 1.0 percent, so that the
comparison would be fair.
As you can see, the results are just
the reverse of what is implied by an
uninformed reading of the specifica-
tion listings given earlier. Amplifier A
produced 68 watts under these condi-
tions, Amplifier B produced 50 watts,
while the amplifier with the highest
"published" power rating-Amplifier.
C-produced only 48 watts.
In the example, we were dealing
with only a single middle -of -the -band
audio frequency. However, the FTC
rule requires that the power band-
width over which the rated power can
be developed at rated (or less) distor-
tion must be specified as well. Refer-
' 10111l IIIII II
5111111E5111111 111 11111 I
:.uuiiii UPI 111 _I 1
11.1111IIIIIIIii1i11..
I
5 IIIIII=l=:l.,ICC1iiIl
n11111tmIllll
IIIL1T-ti-y-rv-oi A
,
1 j 1011111,
11
II
10 100 K
FREQUENCY -Hz 10K
Fig. 2. Again, amplifier A proves to be much
lower in distortion than amplifiers B and C, in
spite of its more conservative published spec.
ring again to the "published" specifi-
cations given above, each manufac-
turer has complied with this require-
ment. The maker of Amplifier C has
honestly stated that his amplifier will
deliver 65 watts at any frequency be-
tween 400 and 3000 Hz. But most of us
know that the real test of a good am-
plifier is its ability to deliver maximum
power at the frequency extremes. This
is particularly important at low bass
frequencies where musical energy
demands are usually greatest. The
thundering beat of a bass drum calls
for more power than is required when
reproducing the sounds of instru-
ments and voices in the midrange re-
gister.
Reading the specifications of Am-
plifier C, we have no way of knowing
how much power the product can de-
liver (if any) at 40 Hz and lower frequen-
cies, or at what level of distortion. The
curves in Fig. 2 show what the distor-
tion of each of our fictitious amplifiers
might look like even if we were to
use 50 watts/channel as a reference
power level. Again, contrary to first
impressions, Amplifier A comes up
the winner as far as distortion is con-
cerned.
Buyer Beware-Still. So, while the
new FTC rule may alleviate some of
the worst abuses of the industry, it
does not entirely correct them. In fact,
many consumers may falsely con-
clude that, with the FTC in the act, all
product specification sheets are
going to read the same-that they will
be comparing apples to apples.
You can be sure that manufacturers
who have reason to "gimmick" their
specifications will still find enough
ways to obscure the facts. The com-
ponent manufacturers who have al-
ways sought to tell the true perfor-
mance story of their products did not
have to wait for federal legislation to
adhere to truth -in -advertising doc-
trines. They have been specifying con-
tinuous power over the entire audio
range, from 20 Hz to 20,000 Hz, at low
distortion levels and with all imped-
ances defined since long before the
FTC ever heard about watts, decibels,
and THD.
The Institute of High Fidelity (IHF)
hopes, before long,.lo publish more
complete measurement standards for
amplifiers. If adhered to, the new
standards would help to eliminate the
many ambiguities that still remain
prevalent, even in the face of the new
FTC requirements.
40 POPULAR ELECTRONICS
AmericanRadioHistory.Com
MANUFACTURERS of TV receiv-
ers unveiled many innovations
in their 1975 models. For example,
major moves have been made toward
providing brighter, sharper color pic-
tures; tuning is getting closer to the
one -button concept; power -supply
designs indicate a trend toward com-
pensation for anticipated voltage fluc-
tuations caused by power shortages;
and serviceability has been improved
with modular designs and other
niceties. Here are details on what each
major color TV manufacturer is offer-
ing in their 1975 all -solid-state chassis
lines.
Admiral. The latest in Admiral's line
of color TV receivers is the Touch
Tuning M25 chassis. Its main feature
is a tuning system programmed with
toothed cards. Six printed -circuit
cards are used to program uhf chan-
nel number readouts. A seventh is for
programming the remote control
channel selector- to go to the next
higher active channel, bypassing all
inactive channels. The cards are pre-
pared for individual viewing situations
with the aid of longnose pliers.
Once the cards are prepared, they
are inserted into connectors in the
tuner. This permits the viewer to select
a channel from the keyboard or the
remote control transmitter. The chan-
nel appears on the screen, and a sepa-
rate readout indicator displays the
channel number.
In the companion M30 chassis, a
special transformer provides voltage
regulation. The transformer is wound
in such a way that its secondary pro -
BY ART MARGOLIS
duces fixed -amplitude square waves,
with the transformer operated at sat-
uration. The transformer is tuned to
resonate at the line frequency with the
aid of a capacitor.
When the input voltage is nominally
117 volts ac, the clipped output volt-
age is a fixed -amplitude square wave.
Should the line voltage vary (within
±10 percent of nominal), any change
produces an inverse change in the
clipping action. The peak -to -peak
square wave applied to the rectifiers
then remains at about the same am-
plitude.
While the Admiral chassis does not
tilt (it is horizontal), it does slide out for
easy servicing.
General Electric. MB, MC, QB, and
YA are the designations given by Gen-
eral Electric to its 1975 chassis. The
stress is on reliability, quality, and per-
formance. For 1975, GE is introducing
the third generation of its Quadline
color picture tube. In -line gun ar-
rangements are featured in the
Porta -Color 13: and 15 -in. picture
tubes. The tubes have short necks and
90° deflection angles. The necks are
up to 2 in. shorter than comparable
tubes with triangular gun arrange-
ments, which eliminates the bump on
the rear of the cabinet. Also, the in -line
arrangement reduces from 12 to 8 the
number of convergence adjustments
that must be made.
In addition to manual and preset
color, tint, and brightness controls,
there is a Custom Picture Control.
Coupled to the contrast, color, and
brightness circuits, it adjusts all three
parameters simultaneously to main-
tain a balanced ratio.
A One -Touch Color system incorpo-
rates tint lock, avc, and the preset
color tint and brightness. The tint lock
widens the demodulation angle by
cross -coupling B-Y and G-Y at the
output of the chroma demodulator IC.
The seven models in the YA series
have chassis that accommodate about
90 percent of all the electrical compo-
nents. Off -the -module components
are overrated to increase reliability.
More than 95 percent of component
failures are claimed to be repairable
by module replacement, and all IC's
plug in for easier servicing. To further
endear itself to the serviceman, GE
has a lot of the service information
pasted on the inside of the cabinet and
printed on the circuit boards. This in-
cludes layouts, catalog part numbers,
detailed adjustment instructions, and
even the schematic.
In the larger chassis (like the MC
series), a high -voltage quadrupler that
develops 30 kV is used instead of the
usual tripler. Regulation of the 30 kV is
achieved with a three -winding satura-
ble reactor circuit.
Heath Company. The latest kit mar-
vel from Heath is its Model GR-2000
digital color TV receiver. The tuner
uses a varactor diode that eliminates
NOVEMBER 1974 41
AmericanRadioHistory.Com
""T
Philco Model C1922FRW
Sony Model KV -1920
Heath Model GR-2000 with on -screen
channel and optional time
moving parts. An up/down counter
digital programming board has provi-
sions for presetting up to 16 channels
in the vhf and/or uhf bands in any se-
quence, even' repeating channels if
desired. The tuning, activated by a
front -panel control or a button on the
optional remote control transmitter,
sweeps up or down through the 16
preset channels.
The number of the channel selected
can be placed anywhere on the screen
for a preset time of up to 90 seconds,
or it can be set permanently on. The
brightness of the display is adjustable.
And the numerals can be instantly re-
called at any time by tapping the
volume -down button on either the re-
ceiver or the remote control transmit-
ter. The numeral readout is digitally
generated by a special character
generator IC on one of the receiver's
modular boards.
As icing on the readout cake, Heath
offers an optional 12/24 -hour digital
clock accessory that fits into the re-
ceiver. It generates the time in an
hours/minutes/seconds format. The
time is displayed on the screen, simul-
taneously with the channel number.
The receiver's plug-in IC ampli-
fier/fixed-tuned LC filter i -f strip elimi-
nates the need for periodic sweep
alignment. Serviceability is aided by
such niceties as modular circuit
boards, built-in dot generator, slide -
out service drawer, and an illustrated
troubleshooting guide in one of the
manuals. A test meter also comes as a
basic part of the receiver kit.
Magnavox. The latest color TV re-
ceiving system from Magnavox is
called the STAR (for Silent Tuning
At Random), which refers to its
varactor-diode tuner. The viewer can
call up any vhf or uhf channel by
punching buttons on a compact re-
mote control transmitter. The receiver
instantly and silently tunes to the
selected channel. The tuning system
is not sequential; it goes directly to the
selected channel without having to
clunk through all the in-between
channels. A special circuit in the re-
ceiver displays the channel's number
in bright numerals on the upper left of
the screen for about 3 seconds.
Depressing the M (for mute) button
on the remote control transmitter
turns off the sound for 1 minute with-
out disturbing the picture.
The latest in negative guard band
color picture tubes is used in the 13 -
through 19 -in. STAR chassis. These
tybes have a black matrix surrounding
color stripes (not dots). The electron
guns are arranged in -line (rather than
in the usual triad configuration),. re-
ducing the number of convergence
adjustments that must be made. Fi-
nally, the picture tubes' necks are
shorter than usual. (The 25 -in negative
guard band picture tube requires a
wide deflection angle that precludes
an in -line gun arrangement.)
The power supply employs a new
voltage -regulating transformer in a
special circuit whose output main-
tains relatively constant voltage dur-
ing minor changes (a few percent) in
THE NEW 1975 ALL -SOLID-STATE TV RECEIVER CHASSIS
Company Chassis Tuner I -F Strip Channel Muting
Indicator
Admiral M25 Varactor Transistor Selector dial Yes
General
Electric MC Varactor; IC Digital (on
control panel)
No
Heath GR-2000 Varactor
?
IC/Fixed-
tuned LC
On screen
(Time optional)
Yes
Magnavox Star Varactor MOSFET On screen Yes
Panasonic Quatrecolor Detent IC Selector dial No
Philco Boss Varactor - Selector dial No
Quasar QS -3000 Detent vhf - IC Selector dial Yes
Varactor uhf
RCA
Sony
XL -100
KV series
Detent,
Detent `
- - Digital (on
control panel)
Selector dial
No
Sylvania GT-matic II Varactor Transistor Digital Yes
Zenith Chroma-color II
L Varactor Transistor Selector dial Yes
Note: All chassis are solid-state and modular and have negative guard band picture tubes, aft, audio
output jacks, automatic degaussing, and 300/75 -ohm antenna inputs. All have electronic remote
control except Zenith (see text).
-
42 POPULAR ELECTRONICS
AmericanRadioHistory.Com
óq
NEGATIVE vs POSITIVE GUARD BAND
COLOR PICTURE TUBES
In a standard color picture tube, 85
percent of the screen is covered with
phosphor dots, with nothing between
them but an aluminized coating that
covers the entire face of the tube? The
dots are 17 mils across, while the elec-
tron beams are 13 mils in diameter.
This means that the beams cannot
completely excite the dots. In fact, only
about half the area of each dot ever
becomes excited. The part not excited
is required as a "guard band" to pre-
vent degradation of color purity result-
ing from the beams overlapping onto
adjacent dots.
Ambient light is reflected from the
aluminized coating and tends to wash
out the picture. So, a tinted face glass
must be used to reduce glare, Tinting
works, but it also kills about half of the
light from the dots. This system is re-
ferred to as "positive guard band" be-
cause the unexcited portions of the
dots protect purity.
In the "negative guard band" sys-
tem, as employed in many of the latest
color picture tubes, the dots are sur=
rounded by an opaque black material.
The electron beams are allowed to be-
come thicker than the diameter of the
dots by increasing the sizes of the
holes in the shadow mask. The entire
dot can now be excited,.whlle the black
material serves as the guard band. Tint-
ing is not required because ambient
light is not reflected by the black sur-
round. Hence, a full 85 percent of the
light produced by the excited dots
comes through the picture tube's face
plate.
the line voltage. The high -impedance
MOSFET i -f module gives the i -f strip
improved sensitivity and reduces any
tendency to overload.
The STAR's modular design caters
to serviceability. And the vertical
chassis has 20° and 45° tilt positions.
Panasonic. Quatrecolor is the name
of Panasonic's line. The new Quintrix
color picture tube employs a negative
guard band black matrix with an addi-
tional pre -focus lens to make the pic-
ture sharper and brighter by bunching
the electrons into a narrower beam.
The featured 0 -lock oné-button color
system is like the preset control sys-
tems, except that the color and tint are
adjusted on a continuous basis, while
brightness and contrast adjustments
are made via preset potentiometers
with a fixed control.
The electronic remote control sys-
tem permits up/down channel selec-
tion. A "vacation" switch on most
models defeats the Speed -O -Vision
instant -on feature. The vhf dipole an-
tenna is detachable to permit it to be
moved around the room to where it
exhibits the best signal -gathering per-
formance.. This is a convenience if the
TV receiver is set into a permanent 1
location.
i
i
it
Philco. The solid-state modular color
TV receiver chassis from Philco is
called BOSS (for Best Of the Solid
States). It features a 37- to 47 -percent
power saving over last year's hybrid
receiver models, tilt -out front con-
trols, and a built in Invis-A-Tenna with
its own reception selector.
Voltage regulation and suppression
are accomplished by Picture Guard
and Surge Guard in the Philco receiv-
ers. In the event of a sudden voltage
spike, due to lightning or voltage
transients on the power line, a filter
capacitor absorbs the temporary over-
load. Hands-off tuning is accomplished
by a network of automatic circuits.
The viewer engages the Philco Master
Control button and selects a channel.
When the Philcomatic COLOR Con-
trol light comes on, he pulls his hand
away and the receiver automatically
tunes itself.
Quick On replaces Instant Play to
eliminate power wastage by not hav-
ing the picture tube's filaments con-
tinuously powered. The audio still
comes on immediately, while the pic-
ture follows a few seconds later.
Quasar. The "works in a drawer"
people are featuring more serviceabil-
ity, line -voltage regulation, a picture
system responsive to ambient light-
ing, and more simplified and reliable
modules. A special twist -lock connec-
tor is used to simplify removal of the
power supply by the serviceman. This
connector eliminates multiple wire
leads that could have been potential
trouble spots.
Quasar's Insta-Matic system em-
ploys a patented demodulator IC that
works in conjunction with a light -
dependent resistor. The LDR is
mounted behind a honeycomb lens
located on the front panel of the re-
ceiver where it measures the ambient
light and allows more or less current
to flow into the video-chroma circuit.
This automatically raises or lowers the
brightness, contrast, and color to suit
the light level in the viewing location.
On the remote control panel is a
,
k
Choosing channels on Zenith's color
TV receiver line is accomplished
with non-detented slide control
RCA XL -100 Model GT-795
/¡
Panasonic Model CT -934
NOVEMBER 1974 43
AmericanRadioHistory.Com
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3. WITH SUPER INSTA MATIC ON,
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GE's MB chassis, uses saturable reactor (T1704) for high volts e regulation.
44
volume -step IC/LED system. Volume is
muted or varied by the differences in
brightness produced by the LED's
glow. In the receiver is a Slumber Sen-
try circuit. It samples the vertical and
composite sync pulses. If the receiver
is left on after the station signs off, the
Slumber Sentry detects the loss of
sync pulses. Then it automatically
shuts off the receiver following a short
delay. [Panasonic recently purchased
Quasar from Motorola-Ed]
RCA. Continuing its XL -100 color TV
receiver system, RCA has shaped up
the 1975 line by installing an elec-
tronic digital display for the vhf and
uhf channel numbers. The display is
on the control panel, rather than on-
screen.
There are no more tubes (except for
the latest negative guard band color
picture tube) in the RCA lineup. The
instant -on feature common in earlier
XL -100 models has been eliminated in
a move toward energy conservation.
Going all solid state and eliminating
instant -on, RCA claims an energy sav-
ings of 27.5 percent over its tube -type
receivers.
The concentration in the XL -100 line
is on the Acculine portable color TV
receivers. The deflection yoke is per-
manently bonded to the Acculine pic-
ture tube (which, incidentally, has an
inline electron gun arrangement) to
prevent it from shifting position.
Hence, the yoke is an integral part of
the picture tube.
Between the Acculine tube and the
bonded yoke, there are only four
dynamic convergence adjustments
instead of the usual 12 that must be
made for setting up the receiver. There
is also only one purity adjustment
-the purity magnet-instead of the
usual two. The second purity adjust-
ment-the yoke-is already fixed in
the correct position.
Sony. Sony this year offers the KV
color series, featuring its Trinitron sys-
tem, which uses color stripes in a
negative guard band matrix, and an
in -line gun arrangement, and the TV
transportable lifestyles line. Sony in-
corporates 114° wide-angle deflection
picture tubes and Econoquick in-
stant -on features for greater viewer
pleasure and convenience. One of the
major benefits of the Trinitron system
is the elimination of costly, time-
consuming set-up adjustments that
conventional three -gun color systems
require.
POPULAR ELECTRONICS
AmericanRadioHistory.Com
I]
The KV series features one button
control for Automatic Fine Tuning,
Color and Hue for accurate and simple
color reception adjustment. Optional
accessories for the Sony line include
rechargeable battery packs, car bat-
tery cords, sun glare filters and auto
and home antennas.
Sylvania. The new Sylvania chassis,
called GT-matic II, is said to add
another dimension to no -button tun-
ing. Parroting preset adjustments, the
viewer simply turns on the power and
selects the channel. Then, the receiver
automatically sets the proper volume,
brightness, contrast, color, tint, and
other major tuning requirements. Au-
tomatic vertical and horizontal holds
and Perma Tint supplement the preset
controls. A pushbutton varactor tuner,
muting, instant -on, remote control,
and 100 -percent solid-state chassis
round out the GT-matic II's features.
The automatic vertical and horizon-
tal holds are controlled by a six -
section IC that produces a syn-
chronized horizontal and vertical scan
system. Other automatic circuits work
on reducing airplane flutter, maintain-
ing a constant voltage, etc.
The Perma Tint circuit acts as a
monitor to maintain color at preset
levels. It attempts to reduce flesh -tone
changes. Once the hidden controls
are adjusted as desired, the Perma
CRT
FILAMENTS
Quasar's 100 -percent
solid-state chassis'
modular design system
Tint control can be activated, increas-
ing the demodulation angle between
R-Y and B-Y to provide a wider
range of phase angles for determining
the actual color of the flesh tone.
The red demodulator IC gates the
Perma Tint on only when there is a
positive component of R-Y present.
This limits the effect of the increased
angle to only those colors in the flesh -
tone range without affecting the
yellow -green, green, cyan, and blue
colors.
Serviceability in the GT-matic II
chassis is supported by plug-in de-
vices and modular arrangement of the
pc boards.
Zenith. For 1975, Zenith is introduc-
ing its Chromacolor II receiver line. It
MAUI
AMPLITUDE
Admiral's power supply system
features fixed -amplitude =
outputs that minimize, voltage -
reduction effects over a
uiide range of variations.
features an all -solid-state vertical
chassis, voltage regulation, and one -
button preset controls.
The Space Command remote con-
trol transmitter still uses a mechani-
cal, rather than an electronic, scheme.
A tiny hammer in the transmitter
strikes a rod that then vibrates at a
specific frequency. The sound thus
produced (it's beyond human hearing)
activates the specific control channel
in the remote control receiver.
Cr.
' ' .
r -
.-
. " t i ' -
. i
Magnavox's remote -control system
features on -screen channel
number in seven -segment format.
Zenith calls its modular construc-
tion "plug-in/pull-out" Dura -Modules.
Eight modules accommodate 75 per-
cent of the circuitry in the receiver.
Tuning in the Zenith receivers is ac-
complished with 14 preset channels
and a slide -switch arrangement. The
presetting need not be sequential.
In Conclusion. So it is obvious that
the consumer has many new features
to look for when buying a 1975 TV re-
ceiver. Of course, he will have to ex-
pect to pay a little more for these inno-
vations. But, in the long run, the initial
investment may be returned to him in
the form of fewer service charges and
an increase in the life of the set. O
NOVEMBER 1974 45
AmericanRadioHistory.Com
THE FCC now allows FM stations
to use a combination of Dolby
B -Type noise reduction and reduced
pre -emphasis in their signal process-
ing. Here's why the new proposal was
accepted and how it affects the per-
formance of your FM tuner.
For years, many responsible people
in the broadcasting field have pri-
vately or publicly suggested a reduc-
tion in pre -emphasis. This process
was introduced in the early days of
FM. It boosts the level of high -
frequency content by passing the
baseband signal through an RC
high-pass filter with a 75-ps time con-
stant, a break frequency of 2.123 kHz,
and a 6-dB/octave slope. In this way,
the S/N (signal-to-noise) ratio of the
FM channel is increased. At the re-
ceiver, de -emphasis must be intro-
duced to balance the spectral content
of the received signal as in the original
information. The de -emphasis net-
work is a simple low-pass RC filter,
with a -6-dB/octave slope, a 75-ps
time constant and 2.123 -kHz break
frequency. The time constant was
chosen at a time when there was mar-
ginal high -frequency content, by
today's standards, in recorded sound.
A low break frequency was required to
radically boost the highs to prevent
them from being lost in the high -
frequency noise that is characteristic
of FM.
Today, we have reached a point
where the recording media can give
much flatter frequency response.
Anyone who has compared an old and
a recent recording of a certain piece
will note a dramatic increase in high -
frequency content, or a more "bril-
liant" sound. This presents problems
to FM broadcasters, though. They are
constrained to a frequency deviation
of 75 kHz, and with increased high -
frequency content, they must either
lower the modulation index, or use
high -frequency limiting. Stations with
integrity wil not color the sound of the
modulating signal, and thus lose some
of their potential audience to less
scrupulous, but louder competitors
who shape the spectral content of the
baseband signal to achieve higher
levels of modulation while staying
within the law.
The proposal by Dr. Dolby will re-
dress the inequities of the situation. If
the level of pre -emphasis were re-
duced, using a 25-ps time constant
and 6.36 -kHz break frequency, sta-
tions could modulate their carriers
more fully, and their signal strengths
NEW
DOLBY -
ENCODED
F
BROADCASTS
would increase an average of 4 dB.
However, the sound from the millions
of FM tuners already in use, with their
75-ps de -emphasis networks, would
be exceedingly dull. Obviously, the
FCC could not allow such incompati-
bility to be introduced. If FM stations
simultaneously change the time con-
stant of their pre -emphasis networks
to 25 psand incorporate Dolby B -Type
noise reduction, an interesting situa-
tion arises.
The reduction of high -frequency
brilliance caused by pre -emphasis re -
FM TUNER
OUTPUT
Z.IK
3900PF 20K
RECORDER
OUTPUT
75ps 25p
FM CAL.
10K
TAPE CAL.
IOK
FM
TAPE
duction is almost completely counter- '
balanced by the effects of B -type
compression. In low -to -medium -
quality equipment, there is no notice-
able difference, and the increase in
the highs noticed from medium -to -
high -quality equipment can be com-
pensated for by a slight reduction of
high response of the amplifier using
the treble control(s).
Brilliance is a subjectively meas-
ured quantity, and to ascertain the ef-
fects of B -type encoding, several sta-
tions switched unannounced to the
new system. Many listeners wrote let-
ters praising the increased quality of
the sound. Not one complaint was re-
ceived.
For those with conventional receiv-
ers and no noise reduction, there will
be a reduction of high -frequency dis-
tortion, and an increase in brilliance
and program level. Listeners equipped
with 25-ps de -emphasis and Dolby B -
Type noise reduction, as produced
now by Dolby licensees as per Dolby's
advice, will receive four benefits: im-
proved signal to noise ratio; full pro-
gram dynamic range, even at high fre-
quencies; better reception in weak -
signal areas; and reduced likelihood
of SCA interference.
Some tuners and receivers are al-
ready equipped to receive the 25-ps
Dolby encoded FM broadcasts. If a
75/25 switch is on the back of the unit
it should be set at 25 during reception
of all subsequent Dolby FM broad-
casts. Otherwise, ordinary B -Type
noise reduction units can be easily
adapted to take advantage of the new
broadcast technique by installing the
FM Compensator shown in the dia-
gram. Only one channel is illustrated;
two will be required for stereo recep-
tion. Anyone may build a compensator
for personal use or manufacture it for
resale without a license. The parts are
inexpensive and may be obtained
from any electronics supply house.
The unit does not require a power
supply.
The PLAY CAL controls on the noise
reduction unit should be turned to
TO "FROM RECORDER"
INPUT ON NOISE-
REDUCTION UNIT
FM compensator provides choice
of 75- or 25-ps time constant.
maximum, and TAPE CAL control on the
compensator used in their place. FM
CAL should be set so that the DOLBY
TONE broadcast by the desired station
gives .a DOLBY LEVEL reading on
the meters of the noise reduction
unit.
46 POPULAR ELECTRONICS
AmericanRadioHistory.Com
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NOVEMBER 1974 47
AmericanRadioHistory.Com
A
BY JIM WHITE, W5LET
41,
5 5
Good AM-SSB-CW
performance
at a fraction of
a superhet's
cost
PRESECCCTOH
P BUILD A
d
DIRECT -
CONVERSION
COMMUNICATION
RECEIVER
AN essential ingredient for the
neophyte in amateur radio is a
good receiver-one that is sensitive
enough to pick up signals that are
down near the noise level and selec-
tive enough to separate adjacent
signals and provide clear copy. With-
out such a receiver, one can only look
forward to "unanswered" CO's and
lots of frustration. However, a good
communications receiver can cost
anywhere from $250 to $500, and most
beginners don't have that kind of
money. Even a good used receiver can
cost $150. As an alternative, a direct -
conversion receiver should be tried. It
performs well over a range of 3.5 to 4.3
MHz on AM, SSB, and CW and is easily
constructed at a cost near $30.
Direct conversion is a much -
neglected type of design that can best
be described by comparing it to the
more common system, superhetero-
dyning. In the superhet system (Fig. 1),
the first stage is an r -f amplifier. This is
followed by a mixer where the signal is
combined with the output of a local
oscillator. The frequency of the latter
is a certain amount above or below
that of the r -f and the difference is
called the intermediate frequency.
The output of the mixer contains a
high -frequency component and a
low -frequency component.
These two signals are produced by
superheterodyning; that is, combin-
ing two signals to produce one at a
frequency equal to the sum of the fre-
quencies of the original signals, and
one at a frequency equal to their dif-
ference. At this point we filter out the
high -frequency component and am-
plify the lower in a stage that has high
gain and a narrow passband, which
affords selectivity. The output of the i -f
amplifier is sent to a detector, which
may be of two types: for AM reception,
it is an envelope detector (a diode fol-
lowed by a low-pass filter); for SSB
and CW, a product detector, which is
really a second mixer, fed by a
beat frequency oscillator (BFO), is
used. The difference component of
this heterodyning process is an au-
dio signal, which is then ampli-
fied through one or more stages and
passed on to phones or a speaker.
As you can see, there are usually
four or more stages that must be
properly tuned in conjunction with
each other for proper signal recovery
in a superhet receiver. Most quality
communications receivers have two
or three i -f stages, with separate mix-
ers, local oscillators, and tuned amp-
lifiers for each stage. These complica-
tions drive the cost of receivers out of
the reach of a large portion of new-
comers to the hobby.
The direct -conversion technique is
a much simpler process. The block
diagram of this system is shown in Fig.
1. The r -f amp supplies the mixer with
an amplified version of the signal re-
ceived from the antenna. The mixer is
also fed an r -f signal of the same fre-
quency as the incoming carrier from a
local oscillator whose frequency is ad -
48 POPULAR ELECTRONICS
AmericanRadioHistory.Com
justed by the main tuning dial. The
output of the mixer contains one
audio frequency signal and one r -f
signal at twice the frequency of the
original. The r -f signal is then filtered
out by a low-pass filter and we are left
with an audio signal. This is then am-
plified by one or more stages of high
gain and the output is connected to a
speaker or a pair of phones. That's all
there is to it. We have none of the
complexities of dual- or triple -con-
version superhet receivers; .but do
have good sensitivity, and if we use a
high -quality, narrow audio filter, we
have selectivity that will rival that of a
superhet unit costing ten to twenty
times more. The simplicity of opera-
tion is reflected in the ease of con-
struction.
Circuit Operation. A comparison of
the block diagram (Fig. 1) and the
schematic diagram (Fig. 2) will point
out a few differences. For economy's
sake, an r -f amplifier has been omitted
from this receiver. However, the re-
ceiver is still sensitive enough to pick
up many signals that would be missed
with a cheap "communications -type"
superhet model. Signals from the an-
tenna are coupled to the MOSFET
mixer, Q1, over the tuned LC circuit
composed of L1, Cl, and C2. Transis-
tor Q4 is the local oscillator and its
output is coupled through a small
silver mica capacitor, C28, to the sec-
ond gate of Ql. The antenna coil, L1,
and the oscillator coil, L2, are wound
on small toroidal cores, which is an
effective way of attaining high Q cir-
ANTENNA
LOW-LEVEL
R -F
R -F
AMPLIFIER
cuits, which are the basis of the selec-
tivity of the receiver's front end.
The other contributor of selectivity
in a direct conversion receiver is the
audio filter. This filter performs two
functions. It rejects the high -fre-
quency component of the mixer out-
put, passing the audio signal, and it
provides a large part of the receiver's
selectivity by virtue of its audio band-
pass characteristics. In this circuit, L3,
C5, C7, and C8 comprise the low pass
filter. Coil L3 is a variable TV width
coil, and the capacitors are of the
Mylar type.
Transistors Q2 and Q3 are conven-
tional audio amplifiers, and almost
any npn silicon transistor will work
well in this circuit. Variable resistor
R10 serves as a volume control in the
standard voltage divider mode and
/01 serves as a high -gain audio output
amplifier. Any one of the common
audio modules furnishing 0.5 to 1 watt
output can be utilized for this purpose.
If desired, a headphone jack can be
installed as in Fig. 2.
A power supply was not incorpo-
rated into the receiver. A suitable
source supplying 500 mA at 9 volts
should be used. If you intend to use
the receiver for portable operation, or
don't wish to construct a supply, six D
cells in series will work perfectly. An
inexpensive plastic holder can be ob-
tained for handling them. It is impor-
tant to take care in observing polar-
ities while connecting the supply. To
protect the sensitive semiconductors,
diode D2 has been incorporated. If the
wrong polarity is applied to the re -
SUM aDIFFERENCE AMPLIFIED
AMPLIFIED R -F (-DIFFERENCE
ANTENNA
`\I/ LOW-LEVEL
-F
MIXER
R -F
AMPLIFIER
I -F
AMPLIFIER
(A)
-\AMPLIFIED R -F
MIXER -.
DETECTOR
SUN (R -E)
!AMPLIFIED
AUDIO SIGNAL AUDIO
AUDIO
AMPLIFIER
SPAR
AMPLIFIED -
DIFFERENCE (A -F) AUDIO SIGNAL AUDIO
AUDIO
FILTER AUU IO
AMPLIFIER
SPKR
(B)
Fig". 1. Several stages are tuned simultaneously in superhet (A).
Direct -conversion receiver (B) is much simpler to operate.
ceiver, D2 is reverse biased and will
not conduct. If this diode was not in-
stalled, the transistors and the IC
would be destroyed in the event of ac-
cidental reversal of power supply po-
larity. However, when incorrect polar-
ity is applied, the receiver simply will
not work, thanks to the protective ac-
tion of D2.
Construction Details. The receiver
was assembled on a 7" x 9" x 2"
aluminum chassis. Two separate cir-
cuit boards were used, and laid out on
the chassis as seen in Fig. 3. The two
cutouts for the boards should be made
following this scheme, but layout is
not critical. The use of individual
boards for the r -f and audio stages
eases troubleshooting as well as con-
struction.
Mount the components on the audio
board first. When you have done this,
position the board in its cutout and
secure it to the chassis. Connect the
positive lead of the power supply to
the center -tap of the transformer and
the negative lead to the chassis
ground. Then connect a speaker to the
secondary of transformer Ti. If you
have correctly assembled this board,
you will hear a hum or buzz from the
speaker when you touch the base lead
connection of Q3. The remaining
board can then be assembled and
mounted on the chassis. Try to keep
all leads as short as possible.
After the boards are in place, spray a
7" x 10" piece of 1/4" masonite with
aluminum paint. When it has dried,
mount the tuning dial on the panel,
and secure the panel to the chassis.
Mount the oscillator tuning capacitor,
C26, on a small bracket, and insert the
shaft of C26 into the dial drive
mechanism. After you have made sure
that the shaft is correctly lined up, fas-
ten the bracket to the chassis. Using a
pair of pliers, turn the tuning
capacitor's shaft until the plates are
fully meshed. Then turn the dial to the
9 o'clock position and tighten the
setscrew on the shaft receptacle. You
can then log frequencies on the dial
using a crystal calibrator or an accu-
rate VFO. The audio gain control, R10,
and the preselector capacitor, C2, are
mounted in 3/8" holes in the front of the
chassis. Drill the holes all the way
through the front panel. Three holes
must be drilled through the back of the
chassis, for the antenna and speaker
jacks, and the power supply leads. If
you choose to include a headphone
jack, it can be mounted either on the
front or the rear of the chassis.
NOVEMBER 1974 49
AmericanRadioHistory.Com
JI
ANT.
C26
100pF
l2*
LI*
iPSEE TEXT
61 73
200p1100pF
1C25 C28
180pF 5pF
C27
^'", 50pF
R2
100K
HEP-F2007
01
Sil
20yF1 AIyF
04
MPF102
PARTS LIST
,,10011.
C24
A05pF
C1 -200 -pi, 500-V sil"ver mica capacitor
C2,C26-Variable 100-pF capacitor
C3-21-pF, 50-V disc ceramic capacitor
C4 -20-µF, 15-V electrolytic capacitor
C5,C8-0.02-1.1F, 100-V Mylar capacitor
C6 -50-µF, 15-V electrolytic capacitor
C7 -0.01-µF, 100-V electrolytic capacitor
C9, C10,C20-5-µF, 15-V electrolytic
capacitor
C11,C12,C13,C15,C22,C23-0.1-µF,
50-V disc ceramic capacitor
C14 -10-µF, 15-V electrolytic capacitor
C16,C17,C18-l00-µF, 15-V electrolytic
capacitor
C19 -1-µF, 15V electrolytic capacitor
C21,C29-0.01-µF disc capacitor
C24,C30-0.005-µF disc capacitor
C25-180-pF, 500-V silver mica capacitor
C27-50-pF, 500-V silver mica capacitor
C6 +
50pF
+ CI7
100pF
C20
C21 5pF +
.01yh T
.OIpF
CA3020
3
R18
4.7K 6
02
2N5665
CIO
51F
R7
536
4 C22 -_
7 + IpF
C18
100
yF C23
Í"-- .IyF
. C28-5-pF, 500-V silver mica capacitor
D1-IN914 diode
D2-Silicon power diode (100 PIV, 750
mA)
I IC1-Integrated circuit (RCA CA3020)
J1-Chassis-mounting coax connector
J2-Phono jack
J3-Two-circuit phone jack (optional)
L1-34 turns No. 22 wire tapped 11 turns
from ground end
L2-34 turns No. 22 wire tapped 5 turns
from ground end
L3-TV width coil, 10-50 mH (Miller 6319
or equivalent)
QI-Dual-gate MOSFET, (Motorola
HEPF2007)
Q2,Q3-2N3565 transistor
Q4-JFET (Motorola MPFI02)
R1 -100,000 -ohm
R3 -560 -ohm
CII'/.IpF
C13
.IyF
RII
39K
03
2143565
SI 9 VOLTS
TM
C30
.005pF
J2
J3
R4 -2200 -ohm
R5,R15,R17,R19-100-ohm
R6 -3300 -ohm
R7 -33,000 -ohm
R8 -390 -ohm All resistors
R9,R14-2700-ohm ' h -W, 10%
RI 1 -39,000 -ohm
R12 -3900 -ohm
R13 -470 -ohm -
R16 -470,000 -ohm
R 18 -4700 -ohm
R20 -27,000 -ohm
R10 -10,000 -ohm potentiometer
Sl-Spst switch (part or RIO)
TI-Transformer: 200 -ohm CT primary;
3.2 -ohm secondary (Calectro D1-729)
Note-Q1 ($1.65) and T50-2 toroids (3 for
$1) are available from Circuit
Specialists, Box 3047, Scottsdale, AZ
85257.
Fig. 2. Receiver employs-toroid-wound coils for L1 and L2. Q1 is a dual -gat.' MOSFET.
Other Frequencies. The receiver
can also be used on other frequency
bands. Only the LC combination at the
input of the mixer and the tuned cir-
cuit of the local oscillator need mod-
ification.
For forty -meter operation, remove
Cl. Remove L2 and replace it with 15
turns of No. 22 enamelled wire, wound
uniformly spaced on a T50-2 toroid,
and tapped 7 turns from the ground
end. Also, connect a 225-pF silver
mica, 500-V capacitor in parallel with
C25. For twenty meters, remove Cl, and
wind a new oscillator coil, L2, on a
T50-2 toroid core. It should be 7V2
turns of No. 22 enamelled wire, evenly
spaced, and tapped 21/2 turns from the
ground end. Remove the 225-pF
capacitor across C25, if it was in-
stalled for 40 -meter operation.
50
For ten and fifteen meters, Li, the
antenna coil, must be replaced with 8
turns of No. 22 enamelled wire, wound
on a T50-2 toroid core. Then L2 must
be replaced with 5 turns of No. 22
enamelled wire, tapped 2 turns from
the ground end. In winding both coils,
spread the turns to space them evenly
around the forms.
Alignment. Making sure that you ob-
serve correct polarities, connect a
9 -volt power supply to the receiver.
Connect a speaker and antenna to
their respective jacks. Turn the audio
gain control until you feel it click, and
then advance it further until you hear
the "rushing" sound of atmospheric
noise. Rotate the preselector
capacitor, C2, slowly. At one point
there will be a noticeable increase in
sound from the speaker. Carefully ad-
just C2 for this peak. There is only one
adjustment for receiver alignment,
setting the value of inductance of L3.
This prevents any r -f components
from local oscillator feedthrough or
the heterodyne process from entering
the audio stages of the receiver. The
procedure is very simple. Adjust L3
until the tuning slug is positioned
about half -way into the coil. This com-
pletes receiver alignment.
Operating the Receiver. As you
tune across a band, keep the front end
of the receiver resonant by adjusting
the preselector capacitor. You will
notice one basic difference in receiver
operation between the direct conver-
sion receiver and a superhet. On the
conventional receiver, there is a mode
switch which must be adjusted for the
type of signal you want to receive.
POPULAR ELECTRONICS
AmericanRadioHistory.Com
P
. .
y
L,
J
0
. .
When this switch is in the SSB/CW
position, it activates the BFO and pro-
duct detector. It is not possible to
properly demodulate such signals
when the switch is in the AM position,
which directs the signal to a simple
envelope detector. With the direct
r.
J2 Jb
c21-+
..C19- +
-C20-41+
1 -C13 -4a
Fig. 3. Etching and drilling
guides for audio and r -f
pc boards are at left and
bottom left. Component layout
guides for r f and audio
boards are shown immediately
below and at bottom.
JCN ASSIS'
D
C4 --
._ -R3- I--R2-
C 26
` 4- L2--
-C271
-R20-
C26
-CII
-C30- sCI6
R14--
C.
' ---R11-41 =B, 03
Fit
..-RI2-, E
Fit
WIPER
. CHA 11
-- RI3 -40
4-C14-7}
NOTE : C7 MOUNTS ON LUGS OF L3
conversion receiver, no such switch-
ing is necessary and any signal (CW,
AM, SSB, or FM) is properly detected
just by adjusting the frequency of the
local oscillator, which is accom-
plished by turning the main tuning
dial.
+
CI6
02
01
GI
1
R19
C24
02
C E
6
CI7
+ -C6--
Thus, the direct -conversion receiver
provides many advantages over the
superheterodyne model. It is less ex-
pensive, easier to build, and simpler to
operate. Why not try something
different-you'll be pleasantly sur-
prised. OO
NOVEMBER 1974 51
AmericanRadioHistory.Com
L
e
t
-r-- ".`
ti
7.ppQO©NMSPER
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.
6
:CONSTRUCTION
o
Measure Low Millivolts
with a Multimeter
HAVE you ever needed a simple
device that would let you ex-
pand the ranges of your multi meter so
that you could measure low -millivolt
ac and dc voltages? Perhaps you need
a small amplifier for checking out the
high-level inputs of an audio amplifier.
Well, the decade meter range expand-
er described here will do both and
more.
The decade range expander can be
used to increase the usefulness of a
multimeter by adding ranges divided
by 10 and 100. It can also be used on
decibel scales, subtracting 20 or40dB
from the existing ranges in your VOM.
Use the expander as a sensitive signal
tracer to obtain quantitative mea-
surements of the signal level at points
of interest, or to read voltage amplifier
stage gain directly in decibels on your
52
Range expander increases sensitivity by X10 or X100
p
yy ofni {
, r1 .'-.- ,
_.
BY JOHN F. HOLLABAUGH
I
t,
.
,'--
Owing to simplicity of circuit,
pc or perforated board
construction is equally suitable.
POPULAR ELECTRONICS
AmericanRadioHistory.Com
PARTS LIST
B1; 132 -9 -volt battery
C1-3-pF capacitor
C2, C4 -1-12.F, 15 -volt .electrolytic
capacitor -
C3-100-pF capacitor
IC1-709 operational amplifier
IC2-741 operational amplifier
J1, J2-Phono jack
R1 -3900 -ohm, 1/4 -watt resistor
R2 -37 -ohm, '/-watt resistor
R3 -1500 -ohm, '/a -watt resistor
R4, R 11-1-megoh m, '/4 -watt resistor
R5, R6 -10,000 -ohm, 1/4 -watt resistor
R7 -10,000 -ohm trimmer potentiometer
R8, R9 -25,000 -ohm trimmer potentiome=
ter
RIO -100,000 -ohm potentiometer
R12 -100,000 -ohm linear potentiometer
SI-Spdt toggle or slide switch
S2-Dpdt slide or toggle switch
S3-Spst toggle or slide switch
S4 -4 -position, double -throw -slide switch
Misc.-Cliassis box, 9 -volt transistor bat-
tery clips, shielded cable and audio
phono plugs (for test cables), IC sock-
ets or Molex Soldercons'l, pc_board or
perforated phenolic board and solder
-clips, hookup wire, solder, hardware,
control knob, etc.
meter. You can even use the range
expander to measure the output volt-
age of a phono cartridge. Try that with
an ordinary multimeter.
About the Circuit. The range ex-
pander makes use of two operational
amplifier IC's (IC1 and 1C2 in the
schematic), exploiting the particular
advantages of the types 709 and 741
op amps. A monolithic amplifier using
bipolar transistors appears to the
signal being processed as a series of
resistances and shunting capaci-
tances. An RC system like this forms a
phase -shift network that at some fre-
quency will cause the amplifier to os-
cillate.
Compensation is required to insure
low gain at the frequency at which os-
cillation occurs. The 741 op amp is
unconditionally compensated. (Gain
is reduced to unity at the point where
oscillation is possible.) The 709 op
amp is not internally compensated,
requiring external components to ob-
tain the necessary compensation.
However, it can be compensated for
frequencies up to 1 MHz, while the 741
is restricted to a top -end frequency of
about 1 kHz by its internal compensa-
tion. The 741 op amp has provisions for
input offset nulling, which makes it
operate well as a dc amplifier. In the
range expander, the 741 (IC2) is used
as a dc amplifier with output nulling
Two operational amplifiers (ICY and IC2) form heart of expander.
and a feedback network that mini-
mizes drift. The 741 has input over -
voltage protection and output short-
circuit protection, while the 709 has
neither. To próvide input overvoltage
and output short-circuit protection for
the 709, R1 and R2 are used.
The 709 (IC1) in the range expander
is compensated for a 40 -dB gain up to
about 200 kHz by Cl , C3, and R3. It has
a feedback network consisting of R4
and R5. Both ac and dc amplifiers (IC1
and IC2) have a common vernier con-
trol (R12) that can be used where
exact values of gain are not required.
The incoming signal (or voltage) is
applied viaJi , while the mode of oper-
ation (ac or dc) is selected with S2.
Switch S1 permits selection of X10 or
X100 in the dc mode, while switch S3
applies power to either the IC1 or the
IC2 circuit. The final switch, S3, per-
mits the range expander to be by-
passed when in the DIR position. In this
position, it routes the incoming signal
at Ji directly to output jack J2. (Note:
When S3 is in the DIR position, S4 can
be switched to off to conserve battery
life.)
Construction. Assembling the range
expander is relatively easy, owing to
the simplicity of the circuit. The entire
circuit can be easily accommodated
inside a 4 in. by 23/4 in. by 2 in. metal
utility box, with the four switches and
vernier control R12 mounted on the
top of the box for convenience.
You can use a printed circuit board
of your own design or perforated
phenolic board and solder clips for
mounting the IC1 and IC2 amplifier
circuits inside the box. JacksJl andJ2
can be mounted at one end of the box.
When the circuit has been fully as-
sembled and all parts are mounted in
place, use dry -transfer letters to label
the control, switches, and jacks.
Calibration. With the range expand-
er switched to DC (bothS2 and S4 must
be set to this position) and R12 set for
maximum sensitivity, connect a mul-
timeter set to a low -voltage range ac-
rossJ2. Adjust R7 fora zero indication
on the multimeter's scale.
Connect a variable -output power
supply or a potentiometer in parallel
with a 1.5 -volt battery to J1 and adjust
the supply or pot for a 0.1- to 0.5 -volt
indication on the multimeter's scale.
Adjust R8 for an indication of 10 times
the reading of the input voltage level.
(Use the multimeter to monitor both
the input and output voltage levels.)
Now, decrease the output voltage of
the power supply (or battery/pot
setup) again for a meter reading of 0.1
to 0.5 volt and switch S1 to the X100
position. Adjust R9 for a reading of 10
times the previous meter reading.
With the input disconnected, recheck
the null produced by adjustment of
R7. It necessary, readjust the null.
NOVEMBER 1974 53
AmericanRadioHistory.Com
D IG I TA L
e1 }
THERMOMETE R
á
Build a
VERSATILE
DIGITAL LED
THERM6ZME TER
Low-cost, accurate device can be used as
indoor/outdoor thermometer
heater/cooler thermostat
temperature alarm
fishing thermometer
THE digital thermometer de-
scribed here was designed for
low cost and simplicity, as well as ac-
curacy. If you check the semiconduc-
tor sales ads in this magazine and use
a conventional thermistor, you can
build the thermometer for about $15. If
you decide to use a precision thermis-
tor, the cost will be about $20. Since
the thermometer operates from a
+5 -volt line, it can be used in a car,
54
boat, or camper. With a line -powered
5 -volt supply, it can be used in the
home.
It is possible to use two switchable
thermistors to check temperature
differentials-such as between the
outside and inside, or between two
rooms. If a long lead is used between
the thermistor and the electronic cir-
cuit, the project can be used as a fish-
ing thermometer.
V
BY THOMAS R. FOX
How It Works. The frequency of the
CMOS multivibrator (Fig. 1) depends
on the resistance of thermistor TDR1,
which is determined by the ambient
temperature. Thus, if the temperature
goes up, the frequency of the multivi-
brator goes up, and vice versa. Trim-
mer potentiometer R23 is used to ad-
just the linearity.
The two -transistor multivibrator (Q1
and Q2) automatically resets the two
POPULAR ELECTRONICS
AmericanRadioHistory.Com
TDRI
R23
5K
J2
CI
+5V
IC640n :
I/4
IC6
P. 04
PARTS LIST
C1 -0.027-µF silver mica capacitor
C2 -10-µF, 10-V tantalum capacitor
C3 -320-µF; 10-V electrolytic capacitar
C4 -15-µF, 10-V electrolytic capacitor
DIS1, DIS2-LED display- (Monsanto
MAN -1 or similar)
ICI, IC2-7490 TTL decade counter
IC3, IC4-7447 TTL,decoder/7-segment
driver
IC5-74121;TTL monostable multivi-
brator
decade counters (IC1 and IC2) and
IC5, which triggers the monostable
multivibrator. When IC5 operates, it
closes the CMOS AND gate and allows
the output of the temperature -de-
pendent multivibrator to pass to the
counters. The length of time that IC5 is
on is determined by the value of C2
and the setting of R3.
Construction. The circuit can be as-
sembled on perforated board, using
sockets for the IC's and transistors.
Everything is on one board except the
power supply and thermistor.
Choose an enclosure that will ac-
commodate the board, the power
2N404
IC6-Quad NAND
or similar)
Hl, J2 -Banana jacks
gate
7 }
14.6( Io! -5r
i ICI a
111 M. 7490
3
11
6
8
2
9 12
7
+5V
16
IC3
7447
a b o b t
R8-RI4
'con.
13 121 11110
11 131101 8
9115 14
T1211I
ANI
(UNITS)
6
6
1 c
8
2
IC2
7490
9 12
+5V
.a
7 18
IC4
7447
bode r
13
R15-R21
10011
4 14
9 9
3 3
+:5V
DIS I
sf
I21 I
Ic 10
10 9
MA I
(TENS
15 14
= D1S 2
+5V
Fig. 1. Two gates in, IC6 form inultivibratorr,
whose frequency is determined by resistance
of TDRI. Pulses (cóntrolied by IC5, Q1, and
Q2) are' couñted by _two -decade system IC1, IC2.
R6 -25,000 -ohm, V4-wátt resistor
R8 -R21 -100 -ohm, 1/4 -watt resistor
R22 -22,000 -ohm, 5%'/ -watt resistor
TDRI-1000-ohm, negative coefficient
thermistor (USI 44004, available from
Yellow Springs Instruments, Box 279,
Yellow Vellowl Springs, OH 43587)
Misc. =Suitable enclosure, flexible wire
for thermistor leads, rubber glue,
optional 9 -oz plastic jar and cover,
Optional switch for two thermistors,
mounting hardware and soc(Ce,
(RCA "CD4011
Q1, Q2 -2N388, HEP641 or similar
Q3, Q4 -2N404, HEP739 or similar
R1 -2000 -ohm, 5%, 1/ -watt resistor
R2, R23 -5000 -ohm miniature trimmer
, potentiometer
R3 -50,000 -ohm miniature trimmer pbten-
tiomer
R4, R7 -1500 -ohm, 1 -watt resistor
R5 -50,000 -ohm, 1/4 -watt resistor
supply, and the two readouts. Be sure
you have access to the three trimmer
potentiometers (R2, R3, and R23)
through suitable holes. If you use the
thermistor called for in the Parts List,
you can use an 1800 -ohm fixed resis-
tor for R23. Other 1000 -ohm thermis-
tors will require some adjustment of
R23. For stability, C1 should be silver
mica and C2 should be tantalum.
The on and off times of the display
are determined by the values of R5/C3
and R6/C4, respectively. These can be
varied to suit individual choice of
times.
If the temperature of more than one
area is to be measured, a simple
switching scheme can be arranged
between J1 and J2.
Carefully solder the flexible two -
wire cable to the thermistor and insu-
late the joints. If the thermistor is to be
used only indoors, coat it with some
rubber glue. If it is to be used outside,
it must be protected from the direct
rays of the sun and other weather
conditions. In this case, mount the
thermistor in a plastic jar (about 9 -oz
capacity), being sure to drill many
ventilation holes. The thermistor
(mounted through the cover) should
not come in contact with the jar. The
jar must be positioned so that it does
not get the direct rays of the sun.
NOVEMBER 1974 55
AmericanRadioHistory.Com
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PART 2:
CONCEPTS AND CIRCUITS
1 N PART 1 of our short course in
digital logic, we discussed the bi-
nary number system, binary arithmetic,
and the octal number system. In Part 2,
we are concerned with logic concepts
and circuits.
Boolean Logic. In 1847, George
Boole, a British mathematician, pub-
lished his Mathematical Analysis of
Logic. This booklet did not equate
mathematics with logic, but it did dem-
onstrate how any logic statement can
be analyzed with basic mathematical
relationships. Boole published a much
longer and refined version of his theory
of logic in 1854. To this day, all practi-
cal digital computers and countless
other electronic digital circuits are
based on the concepts pioneered by
Boole.
Boolean logic (or algebra) makes the
important assumption that a logic
statement is either true or false. Since
electronic circuits can easily be made
to operate in either of two states, on or
off, it is convenient to equate "true"
with "on" and "false" with "off." Simi-
larly, we can equate the binary 1 with
on and the binary 0 with off. With the
foregoing in mind, let us review
Boole's basic logic concepts.
The mathematical explanation of
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logic put forth by Boole can be sim-
plified into three basic logic functions:
AND, OR, and NOT. The AND function re-
quires that one logic state or condition
and at least one other be true before
the entire statement is true. The OR
function requires that one logic state
or at least one other be true before the
--0,-r- OW:
O.1'OO
OvT.
OX/ -0 /.rJ_/
AND
m-,
Our -Our.
0#1., OR /tl
-0.. --our our.
= =0
NOT
OuT
Fig. 1. Switches are
arranged to illustrate
three basic digital
electronic functions.
NOVEMBER 1974 57
AmericanRadioHistory.Com
entire statement is true. The NOT func-
tion simply reverses a stazement from
true to false, or vice versa. Electronic
NOT circuits are commonly referred to
as "inverters" because their function is
to invert the polarity of the signal.
The above definitions can be tabu-
lated into a table such as shown in Fig.
1. Such a table is useful in showing the
relationships among Boole's three
logic functions and their electronic
and arithmetic counterparts. This type
of table is sometimes called a "truth
table" since it sets forth the various
logic conditions for which each state-
ment is true. Generally, truth tables are
arranged in a more compact form simi-
lar to those shown for the three basic
logic functions in Fig. 2.
Truth tables can be created for any
logic function. Specification sheets for
digital logic circuits almost always in-
clude a truth table.
our
A B OUT. A B
our A
OUT
our.
A OPT.
0 0 0 0 0 0 0 /
0 / 0 0 1 / / 0
1 0 0 / 0 /
/ / / / / /
Fig. 2. AND, OR, and NOT symbols are
shown with truth. tables.
Logic Symbols. Boolean logic
statements can be implemented by
simply writing them on paper, using
alphabetic symbols to correspond to
"true" and "false" conditions. Elec-
tronic logic diagrams, however, are
much easier to design and interpret if a
sort of block diagram of the circuit is
presented. For this reason, standard-
ized logic -block symbols have been
devised for the three basic logic func-
tions. They are shown in Fig. 2.
Compound Logic.Circuits. Two cir-
cuit combinations (the NOT -AND and the
NOT -OR) are used so frequently that
they are treated as basic logic elements
and given their own logic symbols and
truth tables.
When the AND function is followed by
a NOT statement, the meaning of the
AND function is reversed to NOT -AND,
commonly called a NAND function.
Similarly, when the OR function is fol-
lowed by a NOT statement, the meaning
of the OR statement is reversed to
NOT -OR, commonly referred to as a NOR
function. The logic symbols and truth
tables for the NAND and NOR functions
are shown in Fig. 3.
9 0UT. A 0(JT:
A BOUr A 8 OUT:
0 0 / 0 0 /
0 / / 0 / 0
/ 0 / / 0
1 / O / l 0
Fig. 3. NAND and NOR symbols with
associated truth tables.
DeMorgan's Theorem. About the
same time Boole developed his logic
theories, Augustus DeMorgan was also
developing some fundamental
theories of logic. His most important
contribution, known as DeMorgan's
Theorem, relates the AND, OR, and NOT
functions as follows:
A+B=Áx6.
A x B = Á + B.
The arithmetic symbols + and x mean
OR and AND, respectively. The bar, or
vinculum, over a letter indicates the
NOT function. Thus A means NOT A.
The importance of DeMorgan's
Theorem is that an AND circuit contain-
ing a NOT at each input corresponds to
an OR circuit followed by a NOT. Simi-
larly, an OR circuit with a NOT at each
input corresponds to an AND circuit fol-
lowed by a NOT. This does not equate
the NAND and NOR functions, but it does
mean that NAND circuits can be used to
implement NOR functions, and vice
versa.
Complex Logic Systems. Logic
systems that contain three or more
basic logic elements are termed "com-
plex." One of the simplest of the com-
plex logic systems is the EXCLUSIVE OR
(sometimes written xoR) function
shown diagramatically in Fig. 4. From
the truth table, note that this function is
identical to the OR function with one
important exception: A true condition
exists only when one or the other con-
dition, but not both, is true.
The EXCLUSIVE OR function com-
pletes the connection between
Boolean logic, the binary number sys-
tem, and electronic switching circuits,
for it can be used to add two binary bits.
To see how this is accomplished, as-
sume a logic 1 at input A and a logic 0 at
A e CARRY
sVM
Fig. 4. Logic array for XOR circuit.
input B in the EXCLUSIVE OR circuit
shown in Fig. 4. Since only one input is
enabled (input A), AND circuit 1 does
not turn on. Hence, a 0 is present at the
cARRv output. OR circuit 1 does turn on,
since only one input need be present.
Since the NOT circuit inverts the 0 from
AND circuit 1 into a logic 1, AND circuit 1
has two input signals and is therefore
turned on. The result is a logic 1 at the
sum output. (The circuit has added 0 +
1 to obtain 1.)
The EXCLUSIVE OR circuit is often
called a "half -adder." Try verifying its
operation yourself by adding 1 + 1 in
binary.
Practical Logic Circuits. Figure 1
demonstrated how simple switching
circuits can be used to implement each
basic logic function. However, it is
usually not practical to employ
switches in real systems. Instead,
transistors, SCR's, tunnel diodes, or
other solid-state switches are em-
ployed.
The most commonly used switch in
digital electronics is the transistor.
Relatively simple circuits that combine
diodes, resistors, and transistors can
be used to implement the AND, OR, and
NOT functions. Thanks to integrated
circuit (IC) technology, several or even
dozens of individual logic circuits can
be placed on a single compact silicon
chip. Resistor -transistor logic (RTL)
was once the most popular type of digi-
tal IC, but it has been largely replaced
by the more noise -immune transistor -
transistor logic (TTL) type.
In recent years, field-effect transistor
(FET) technology has been adapted to
integrated logic circuits of amazing
complexity. By insulating the gate of a
FET with a layer of silicon dioxide, ex-
tremely high impedances are made
possible. The result is a logic circuit
that requires microamperes or
nanoamperes of operating current at
relatively low voltages.
Insulated -gate fabrication techni-
ques are collectively known as MOS
(for metal oxide semiconductor) tech-
nology. Since MOS transistors are uni-
polar (p- or n -type) and do not require
separate p and n sections like conven-
tional bipolar pnp and npn transistors,
MOS IC's can have a much higher
component density than most conven-
tional IC's. The result is large-scale in-
tegration (LSI). So, the next time you
read or hear the phrase "MOS LSI,"
you will know _thatit refers to a large-
scale integrated circuit employing
metal oxide semiconductors.
58 POPULAR ELECTRONICS
AmericanRadioHistory.Com
Product
Test Reports
PIONEER MODEL SX-636 AM/STEREO FM RECEIVER
(A Hirsch -Houck Labs Report)
25-wattslchannel receiver with superlative stereo FM tuner section
USED
s
_
p
ROUGHLY in the middle of the
current line of stereo receivers
from Pioneer, the Model SX-636 fea-
tures a tuner section that makes the
most effective use of integrated circuit
technology that we have yet seen in a
hi-fi component. The result is a level of
performance, in a moderate -priced
receiver, that in some respects sur-
passes that of most separate
components-to say nothing of far
more expensive receivers.
The receiver's audio amplifiers are
rated at 25 watts/channel over the en-
tire audio range, with less than 0.5
percent THD. They are operated from
balanced positive and negative power
supplies and are direct -coupled to the
speakers. The preamplifier section
features tone controls with 11 lightly
detented click -stop settings, and a
balance control with a detented cen-
ter setting. The phono preamplifier,
whose gain allows the rated output to
be developed with only a 2.5 -mV input,
can handle signals greater than 100
mV in amplitude without distortion.
The FM tuner section employs a
fairly conventional front end contain-
ing a FET r -f amplifier followed by a
dual ceramic i -f filter featuring linear
phase characteristics. All other FM
functions are performed by a single
large-scale integrated (LSI) circuit-a
proprietary development of Pioneer,
containing circuitry that provides i -f
amplification, five stages of limiting,
NOVEMBER 1974
-
G
and FM (apparently quadrature) de-
tection. The detected signal then goes
to a phase -locked loop IC for multiplex
demodulation. The entire AM tuner
consists of only one IC, plus a handful
of external components. Conse-
quently, Pioneer has made an AM/FM
tuner with only three IC's and a rela-
tively small number of discrete com-
ponents, the performance of which
proved quite exceptional in our
laboratory tests.
The receiver has two pushbutton
switches labelled TAPE MONITOR that
allow two tape decks to be used simul-
taneously, with off -the -tape monitor-
ing from either deck and the ability to
copy tapes from one deck to the other.
The FUNCTION Switch has a PHONO/MIC
position, in addition to the usual AM,
+10
O
10
20
¡ 30
J IV
cz 40
ó
50
60
70
80
FM, and AUX positions. Plugging a mic-
rophone into its jack automatically
disconnects the phono pickup and
applies a monophonic microphone
signal to the preamplifiers of both
channels. Another pushbutton switch
is for the high -cut filter. And for max-
imum convenience, there are two ac
outlets on the rear apron, one of which
is switched.
The Pioneer Model SX-636 AM/
stereo FM receiver comes complete
with a walnut -finished cabinet for a
fair-trade retail price of $349.95.
Laboratory Measurements. The
audio amplifiers of the Model SX-636
receiver clipped at 29.7 watts/channel
with both channels driven simultane-
ously at 1000 Hz into 8 -ohm loads. Into
4 ohms, the power was 36.7 watts,
while into 16 ohms, it was 20.5
watts/channel. The 1000 -Hz THD was
less than 0.1 percent from 0.1 to 30
watts, typically measuring less than
0.03 percent. The IM distortion was
also less than 0.1 percent from 25
watts all the way down to less than 5
mW output.
At the rated 25 -watt output level,
and at one-half and one -tenth of rated
power, the distortion was typically
0.025 percent or less over most of the
audio -frequency range. It never ex-
ceeded 0.055 percent, this at full
power and 20,000 Hz. At normal listen-
ing levels, the THD was about 0.01
percent. Our figures were a great deal
better than Pioneer's very conserva-
tive 0.5 -percent published figure.
A 10 -watt reference output level was
obtained with an input of 75 mV (Aux),
1.25 mV (PHONo), and 3.6 mV (MIc). The
respective hum and noise levels were
-81 dB, -75 dB, and -61 dB. The
PHONO inputs overloaded with a
100 -mV input, and the MIc input over-
loaded with a 275 -mV input.
The bass tone controls had a sliding
MONO I I I I
____STEREO 1
AUDIO OUTPUT AT TAPE OUTPUT JACKS
OdB='VOLT
PIONEER
i
I IIIII
SX-636
FM TUNER SECTION
to ` 1 *TOTAL
RE:100% D STORTION,
MOD. AT NOISE,
1000Hz HUM -
..,.._ T _ _. _
7
if -STEREO
ANALYZER NOISE
WAS CURVE
USED RISES
TO ABOVE
EXCLUDE
,-
THE CURVE UNDER
191,Hz PILOT SIGNAL
209V BECAUSE WAVE NOISE
illii"
10 100
INPUT -MICROVOLTS (9V)
4K IOK 30K
59
AmericanRadioHistory.Com
PIONEER SX-636
REFERENCE POWER (25 1
0.5 HALF POWER (-3dB1
-- - - - LOW POWER I-10dB1
0.2
0.1
05
02 ..... - _ 1...
01
0
50 100 200 500 101, 21111( 5YN, 10 Ha 20
FREQUENCY IN Hz (CYCLES PER SECOND) MN:
turnover frequency that allowed ap-
preciable correction at the lower fre-
quencies with no effect on the mid-
range. The treble tone control's
characteristic was hinged at about
2000 to 3000 Hz. Loudness compensa-
tion boosted both the low and the high
frequencies. The high -cut filter had a
6-dB/octave slope, with the -3 -dB
point at 4700 Hz, while the RIAA
equalization was virtually perfect over
most of its range (less than ±0.25 dB
variation between 50 and 20,000 Hz).
There was a very slight bass roll -off
caused by the loading of the
10,000 -ohm input impedance of our
graphic level recorder on the tape re-
cording outputs where we made the
RIAA measurement. The cartridge in-
ductance had only a moderate effect
on the equalization, about as much as
we have found on most other good
amplifiers. The microphone response
was essentially flat, within ±0.5 dB
from 25 to 6000 Hz, falling off to -1.5
dB at 10,000 Hz.
The FM tuner had an IHF usable
sensitivity of 1.8 µV in mono and 10 µV
in stereo. The 50 -dB quieting sensitiv-
ity was 3µV in mono and 100 µV in
stereo. Ultimate queting was 70 dB in
mono and 55 dB in stereo, while ulti-
mate distortion was about 0.11 per-
cent in mono (very low) and about 0.5
percent in stereo.
0.5
.0101
PIONEER SX-636
CHI TOTAL HARMONIC DISTORTION
- - - - 60/0000(1, (4:111. DISTORTION
TN%
0.2 0 5 2 5 10 20 50 100
CONTINUOUS AND EQUIVALENT
SINE -WAVE POWER OUTPUT PER CHANNEL IN WATTS
+'° O-.
10
30
40
1111111
,FREQUENCY RESPONSE
PIONEER SX-636
FM STEREO
AVERAGE BOTH CHANNELS /
50
-60
1
CROSSTALK ,,--...-
20 50 IDO 200 500 IK 26 6K IOK 2CR
FREQUENCY IN H.
The capture ratio was an impressive
0.7 dB, about the best we have ever
measured in a tuner. AM rejection was
51 dB. Image rejection was 75.5 dB,
alternate -channel selectivity was 63
dB, and muting threshold was 2.2
µV-the last low enough to exclude
noise but not any receivable signals.
Automatic mono/stereo switching oc-
curred at 2.5 µV. The 19 -kHz pilot car-
rier leakage into the audio outputs
was 41 dB below full modulation.
The stereo FM frequency response
was within±0.25 dB from 30 to 13,500
Hz. It was down only 1.5 dB at 15,000
Hz. The channel separation was ex-
traordinary, measuring between 50
and 53 dB over a frequency range of 30
to 2500 Hz. It reduced to 40 dB at
10,000 Hz and was still an extraordi-
nary 31.5 dB at 15,000 Hz. Clearly, this
must be credited to the linear -phase i -f
filters and the phase -locked loop de-
modulator, which operate with re-
markable effectiveness. The AM
tuner's frequency response was down
6 dB at 100 Hz and 5300 Hz.
User Comment. As the above test
data shows, the Pioneer Model SX-636
receiver merits the use of superlatives
in describing some of its characteris-
tics. In particular, the stereo FM sep-
aration taxed the abilities of our signal
generator. In this one respect, the
system's tuner performed in a manner
that has been matched only by a com-
ponent tuner that sells for $2500!
Impressive as our measurements
may appear to be, they cannot ade-
quately describe the performance of
this receiver. It is not enough to state
that the receiver surpassed every one
of its published specifications during
our tests, even though this in itself is a
rather unusual event in our experi-
ence. The real proof is in the using.
The operation of the receiver is totally
smooth, with noise -free muting, very
accurate dial calibration, and not a
trace of switching transients or other
undesirable side effects. One can eas-
ily be lulled into taking these things for
granted, but it is surprising how many
audio components-in all price
ranges-are deficient in some of these
important respects.
CIRCLE NO. 65 ON READER SERVICE CARD
ROYCE MODEL 1-600 MOBILE CB TRANSCEIVER
Moderately priced unit features crisp speech quality
THE moderately price Model
1-600 solid-state mobile CB
transceiver from Royce Electronics
features crystal -synthesized opera-
tion at full legal power on all 23 AM
channels. It has a meter that indicates
relative signal strength on receive and
relative output power on transmit. Ad-
ditionally, the transceiver incorpo-
rates only the main essentials: adjust-
able squelch, a -f volume control, au-
tomatic noise limiting (anl), and
external -speaker jacks for receiver or
PA operation. Supplied with the trans-
ceiver are a detachable dynamic mic-
rophone and mobile mounting hard-
ware. The rig is designed to be oper-
ated from 12- to 13.8 -volt dc, negative -
or positive -ground, electrical systems.
Retail price is $124.95.
The Receiver. The receiver section
POPULAR ELECTRONICS
60
AmericanRadioHistory.Com
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u
r ' :' 09
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62 POPULAR ELECTRONICS
AmericanRadioHistory.Com
Just think how much in demand you would be if you
could prevent a TV station from going off the air by
repairing a transmitter ... keep a whole assembly line
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vent a bank, an airline, or your government from making
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Today, whole industries depend on Electronics. When
breakdowns or emergencies occur, someone has got to
move in, take over, and keep things running. That calls
for one of a new breed of technicians - The Trouble-
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Because they prevent expensive mistakes or delays,
they get top pay - and a title to match. At Xerox and
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What do you need to break into the ranks of The
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kind a good TV service technician has-only lots more.
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As one of The Troubleshooters, you'll have to be ready
to tackle a wide variety of electronic problems. You may
not be able to dismantle what you're working on - you
must be able to take it apart "in your head." You'll have
to know enough Electronics to understand the engineer-
ing specs, read the wiring diagrams, and calculate how
the circuits should test at any given point.
Learning all this can be much simpler than you think.
In fact, you can master it without setting foot in a class-
room ... and without giving up your job !
For over 37 years, the Cleveland Institute of Electronics
has specialized in teaching Electronics at home. We've
developed special techniques that make learning easy,
even if you've had trouble studying before. Our AUTO -
PROGRAMMED® Lessons build your knowledge as
easily and solidly as you'd build a brick wall - one brick
at a time. And our instruction is personal. Your teacher
not only grades your work, he analyzes it to make sure
you are thinking correctly. And he returns it the same
day it is received, while everything is fresh in your mind.
The Science of the Seventies
To keep up with the latest developments, our courses are
constantly being revised. CIE students receive lessons
in Field Effect Transistors, Digital Switching Units,
Microwave Systems, Lasers, Binary Coding and Com-
puter Arithmetic.
In addition, CIE offers an exciting Electronics Tech-
nology with Laboratory course that includes 161 space-
-.
_a
Learn By Doing...
Electronics Technology
with Laboratory Course
teaches you the funda-
mentals. Using space-age
components and testing
techniques youwill apply
the principles you learn
.. actually analyze and
troubleshoot modern
electronics equipment.
age components to let you perform 242 fascinating
electronics experiments. You learn the "how" as well as
the "why" of Electronics ... the Science of the Seventies.
Many leading companies use CIE courses to train their
own employees who are working on the latest electronic
equipment.
Get an FCC License - or Your Money Back!
Two-way mobile work and many other types of trouble-
shooting call for a Government FCC License, and our
training its designed to get it for you. But even if your
work doesn't require a license, it's a good idea to get one.
Your FCC License will be accepted anywhere as proof
of good electronics training.
A good way to prepare for your FCC exam is to take
a licensing course from CIE. Our training is so effective
that, in a recent survey of 787 CIE graduates, better than
9 out of 10 CIE grads passed the Government FCC
License examination. That's why we can offer this
famous Money -Back Warranty: when you complete any
CIE licensing course, you'll be able to pass your FCC
exam or be entitled to a full refund of all tuition paid. This
warranty is valid during the completion time allowed
for your course. You get your FCC License - or your
money back. Mail Card for 2 Free Books
Want to know more? Then fill out and mail reply card
or coupon today. We'll send you our two FREE books on
opportunities in Electronics. For your convenience, we
will try to have a representative call. Act now, and get a
high -paying job that much sooner.
APPROVED UNDER G.I. BILL
All CIE career courses are approved for educational
benefits under the G.I. Bill. If you are a veteran or in
service now, check box for G.I. Bill information.
C IE Cleveland Institute
of Electronics, Inc.
1776 East 17th Street, Cleveland, Ohio 44114
Accredited Member National Home Study Council
I-
e-
Cleveland Institute of Electronics, Inc.
1776 East 17th Street, Cleveland, Ohio 44114
Please send me your two FREE books:
1. Your school catalog, "Succeed in Electronics."
2. Your book on "How To Get A Commercial FCC License."
I am especially interested in:
Electronics Broadcast First Class
Technology Engineering FCC License
Electronic Industrial Electronics
Communications Electronics Engineering
Electronics Technology with Laboratory
Name (PLEASE PRINT)
Address
City State
Veterans and Servicemen:
Check here for G.I. Bill information.
Zip
PE -66 J
NOVEMBER 1974 CIRCLE NO. 7 ON READERS SERVICE CARD 65
AmericanRadioHistory.Com
SSB and CW or a separate diode de-
tector for AM. The audio amplifier is
rated at 3 watts output into a 4 -ohm
speaker load.
The PTO's dial is calibrated at 1 -kHz
intervals from 0 to 500, with about 50
kHz of "overrun" at each end. The
dial's reference mark can be shifted to
calibrate the receiver precisely to any
known frequency. At the upper center
of the receiver's front panel is a small
opening for the frequency range dial,
which is marked to indicate each of
the 10 basic bands, together with the
appropriate settings of the RANGE
switch and the PRESELECTOR control
knob. Decals are supplied for the 13
blank spaces on the dial, to be added
when other crystals are installed.
The front -panel controls include
concentric a -f and r -f gain controls,
mode switch (with positions for AM
CW, LSB , and USB), and an accessory
switch. The last activates an optional
100 -kHz crystal calibrator and i -f noise
blanker when they are installed. Con-
centric with the accessory switch is a
knob that is used to tune the rejection
notch filter through the i -f passband to
reduce interference from hetero-
dynes.
On the rear apron of the receiver are
phono jacks for the antenna and mut-
ing connections and an audio in/out
jack that can be used either to supply a
signal to a tape recorder, ahead of the
volume control, or to amplify an exter-
nal signal through the SPR-4's am-
plifier. There is also a 120/240 -volt line
selector and a switch that disables the
dial lights for low battery drain (only
2.5 watts at 12 volts).
Laboratory Measurements. The
Model SPR-4 receiver has sensitivity
ratings for a 10 -dB (S + N)/N ratio of
0.25 pV on CW and SSB and 0.5 µV for
AM at 30 percent modulation. We
measured the sensitivity at the center
of each band (except the two lowest
where the input impedance is too high
to match our signal generator). It
proved to be substantially better than
claimed and varied little from band to
band.
The CW sensitivity measured better
than 0.15 µV throughout and about 0.1
µV on most bands. The SSB sensitivity
was typically about 0.18 µV and
reached 0.22 µV on the highest and
lowest frequency bands tested. The
AM sensitivity was better than 0.35 µV
and was typically a little better than
0.30 µV.
The agc is stated to hold the audio
level within 6 dB for an input signal
variation of 100 dB. We were able to
check it over only an 86 -dB signal
range, where it varied by only 3.2 dB.
The i -t bandwidths at the -6 -dB points
were essentially as rated: 4.8 kHz on
AM, 2.4 kHz on SSB, and 0.4 kHz on
CW. The dial calibration was within 1 kHz
on all bands, even without "zeroing"
the dial on each range as recom-
mended. When we set the zero at
either end of the tuning range, the dial
was about as accurate as it could be
read-certainly within 200 Hz at all
points. And there was no discernible
drift over extended periods; the rating,
incidentally, is less than ±100 Hz.
The S meter is, of course, a relative
signal strength indicator. On the
7 -MHz band, an input of 1.8 µV gave an
S2 indication, while S9 was attained
with only 17µV of input signal
strength. This is by any standards a
most 'generous'. meter. Furthermore,
a reading of S9 + 20 dB required 38
µV, which is only about 6 dB greater
than the S9 input. To reach S9 + 40
Now available, our latest version of the amplifier that start-
ed it all; the faithful old "Universal Tiger'. We have put
him in a fancy new chassis and added our famous comple-
mentary differential input circuit, but this is still the rug-
ged, low distortion, economical amplifier that thousands of
you out there love so well. With a power output of 75 Watt
into an 8.0 Ohm load, or 90 Watt into 4.0 Ohms the
"Tiger B" is the ideal BASIC amplifier for all types of ap-
plications; from HiFi systems to public address work, to
instrument amplifiers; you name it. With its tremendous
frequency response, -1.0 dB at 1.0 Hz and 100KHz and
super low distortion of .05% I M at rated output, Tiger "B"
is ideal for almost any application using an audio amplifier.
Nothing but the best components and first quality fibre-
glass circuit boards are used in this kit. The chassis is bronze
anodized and the perforated metal cover is standard.
For those who insist on "guilding the lilly" we have an
accessory kit to add an output meter, input level control,
overheat indicator lamp, front panel power switch, etc.
Circle our reader service number for your free copy of our
latest catalog.
# 275 Amplifier Kit (single channel)
# AC -275 Accessory Kit
NOVEMBER 1974
$64.50 PPd
$ 7.90 PPd
tl
Ail Southwest TechnicarProducts Corp:
219 W. Rhapsody,
San Antonio, Texas 78216
CIRCLE NO. 37 ON REA:%cRS SERVICE CARD 67
AmericanRadioHistory.Com
tEV experience
VJ AN three
with
Years o co\\ege
TrcCH,C en `n Ps a
or
0-000 o e $1.9,000
9' oppor
for assignmen
t $,ngook, or engineer-
ing.
cstatfree C`o\ management
anag Pn tegesJ pfl ers
year to move pX an
oppor-
tunity transe ctd'ng
iJ rn
Force Captain,
C,pb.
'f you read an ad like the above
in the classified section of your
newspaper, you might think it was too
good to be true. Hdwever, it accurately
describes many technical representa-
tive and field engineering oppor-
tunities available in the electronics
field. On the whole, a tech rep job pays
well, offers excellent opportunities for
travel, and encompasses a number of
duties.
A tech rep is hired by an electronics
company which, in turn, sells his serv-
ices where needed. The U.S. Govern-
ment, private industry, and local and
foreign governments sometimes need
electronics technicians.for special
projects. So, they often sign a contract
for enough tech reps to get the job
done. The contract might call for .the
tech reps .to do anything from teach-
ing a Job Corps class in New Jersey to
manning a lonely tropospheric scatter
site in Thailand.
On the job, a tech rep's work varies
from assignment to assignment. On
one assignment, he might be an ad-
visor, telling a crew of workers what to
do. On his next assignment, his job
might be to teach a group of students
or working technicians the theory and
operation of new avionics equipment.
Then again, he might operate and
maintain á communications system.
Most tech reps are called upon to do a
bit of everything. In a typical month, he
might spend a few days each at teach-
ing a class in electronics theory, and
practices, helping out on installing or
NOVEMBER 1974
CA
OPPORTUNITIES
FOR THE
CH
renovating electronics gear, and re-
pairing a radio or radar system: -
Tech reps have been known tó óp- -
erate, maintain, and repair computers,
avionics equipment, radar gear, com-
munication's systems, test equipment,
navigational aids, and just about ev-
erything else that uses electronic cir-
cuitry. One tech rep might specialize,
his duties confined to repairing a
single complex transceiver model,
.while.another might be called upon to
repair a dozen or. so different models
and types of equipment. Some tech
reps specialize in teaching.
Án assignment might put a tech rep
in the heart of downtown Manila, right
in the midst of civilization. On the
other hand, assignment locations can
be lonely and far from the amenities of
civilization, such as in the heart of a
jungle or atop a mountain. Assign-
ments can be almost permanent Or
highly mobile, depending on the con-
tract. Some tech reps stay in -the same
location for years, while others must
pack up and _move to.'a 'new location
every few months.
Most tech reps enjoy their assign-
ments, but few find "paradise." The
Manager .of International Recruiting
for Page Communications Engineers
says, "One word -of caution to those
who are tempted to cast all aside and
dash off to unknown places: To the
neophyte who expects to find all the
creature comforts he is -accustomed
to, my advice .is to look before he
leaps.' Instead of some pleasurable
BY ALLAN C. STOVER
off -duty relaxation in exotic Bankok,
he might find himself repairing a radio
(t~ansmitter) on an;isolated mountain-
top in Iran."
Electronics companies employ
thousands of tech reps, stationing
them in every corner of the world. You
can find tech reps in almost every
state of the Union, Germany, on the
island of Crete, in Taiwan, Ethiopia,,
a -id Iran, Vietnam and Korea, Spain,
Turkey,- the Philippines, New Guinea,
Jamaica, the. Arctic, and on some
Pacific islands, and aboard ships and
submarines.
RCA Service Co. Technical Services
Grp-eseutative works on radar unit.
)`" 9 jai
e
AmericanRadioHistory.Com
What and Where. ITT's Federal Elec-
tric Corporation ships their tech reps
all over the world. Sometimes they in-
clude tech rep services as part of a
contract for new equipment. In De-
cember 1973, Federal Electric signed
$56 -million worth of new contracts
and renewals, which gives an idea of
the size of the corporation's opera-
tions. Here are a few of the hundreds
of jobs the Federal Electric tech reps
have handled:
They have installed a microwave
communications system in South
Vietnam. (The South Vietnam gov-
ernment issued a stamp in their
honor.) In Italy, Germany, France, Bel-
gium, England, and the Netherlands,
they installed a tropospheric scatter
system. For years, they have operated
and maintained DEWLine (Distant
Early Warning Line) sites ranging from
Iceland and Greenland to northern
Alaska in some of the bleakest and
frostiest locations inhabited by man.
The Federal Electric Corporation has
held this contract since 1956-almost
two decades.
Federal Electric tech reps per-
formed operational and maintenance
services as the prime contractor on
the Air Force's Western Test Range,
where they manned range tracking
ships and stations, among other
things. They installed a computerized
reservations system in the British
Overseas Airways Corporation's of-
fices in New York.
Tech reps from RCA Service Com-
pany have tackled hundreds of differ-
ent jobs in as many different places all
over the world.
A satellite ground station was instal-
led in the People's Republic of China.
They operated and maintained a track-
ing site in the Arctic, and they oper-
ated and maintained missile tracking
stations on islands in the Atlantic
Ocean for the Air Force's Eastern Test
Range.
The RCA teach reps gave technical
assistance and training to the Philip-
pine, South Korean, Ethiopian, and
Spanish air forces.
Salaries and Extras. Most com-
panies pay their tech reps well. Base
pay usually is on an average with a
RCA Service Co. Government Services Technician
works on Meteorological Data Handling System
Center's computer control console at the
Goddard Space Flight Center.
38R N
- r -' rY 31SA5
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.
00;;
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good technician, but "extras" can
push the total -package up to more
than what the average electronics en-
gineer earns, from $10,500 to $19,000
per year. Overtime can run these fig-
ures even higher. The extras depend
on the company the tech rep works for
and the assignment on which he is
sent. Examples of extras include:
Per Diem: A daily allowance that is
designed to repay the tech rep for
most of his extra expenses. It covers
hotels, meals, cleaning bills, tips, and
other expenses. Per diem is usually a
flat rate; so, if a tech rep cuts corners,
he can pocket the money he saves.
The per diem rate runs from a few dol-
lars up to and beyond $25 per day.
Some companies pay per diem for as
long as the tech rep remains on the
assignment, while others pay it for
three to six months only. Still other
companies pay per diem only when
the tech rep travels on business away
from his regular assignment. A few
companies pay the tech rep's actual
expenses instead of per diem.
Cost -of -Living Allowance (COLA): A
few companies pay COLA to cover the
difference in living costs between a
U.S. city and an overseas location. The
COLA in Tokyo, the world's most ex-
pensive city in which to live, can run
hundreds of dollars a month. One
company gives a flat 30 percent of
base pay no matter where they assign
a tech rep. Some U.S. Air Force con-
tracts direct the local military dis-
bursement officer to pay a COLA to
each rep. COLA can start at $7 per day
on some contracts.
Bonuses: Some companies pay a
flat bonus for overseas service. It can
be 10 percent of base pay or $125 per
month, depending on the company for
which the tech rep works. Some com-
panies pay a bonus that depends on
the location of the assignment; a tech
rep who lives in a soggy tent in South
Vietnam gets a bigger bonus than one
who works in downtown Brussels.
This patchwork of pay and allow-
ances makes it difficult to predict a
tech rep's pay package. But the aver-
age paycheck for tech reps, all extras
considered, runs from $12,000 to
$16,000 per year, with some reps re-
ceiving salaries above and other
below these figures.
The tech rep who works overseas
has an opportunity to take advantage
of one of the juiciest Internal Revenue
tax laws ever written. If he spends 510
days (about 17 months) out of 18
months outside the U.S., up to $20,000
POPULAR ELECTRONICS
AmericanRadioHistory.Com
The Heat':`.
two kinds
of people
who understand
electronics, and
those who don't
People who understand electronics
will appreciate the GR-2000's ad-
vanced digital design, incorporating
on -screen channel readout
and optional clock. Digital
logic circuitry programs
up to 16 stations in any
e, sequence. Then just
press a button-you'll
never have to switch
through a "dead"
` . channel again.
OO And our exclusive
VHF/UHF varactor
tuner eliminates clunking
contacts that corrode and noisy mo-
tors that break down.
The GR-2000 also has
the industry's first
fixed -filter IF am-
plifier. There's no
need for instrument
IF alignment ever, so
the picture stays bright
and clear year after year. And even in
urban areas where stations
are packed closely
together, there's vir-
tually no adjacent
channel interference.
The 100% solid-state
chassis uses 19
integrated circuits-
more than any other TV
around. You'll get
superior performance and reliability
no conventional set can match.
A built-in dot generator and test meter
make it easy to keep the GR-2000 in
peak condition without expensive
service calls. The slide -out service
drawer and hinged, swing -out chassis
There's a new Heat:. 't
everyone on
't Digital Color TV is for
put everything in easy reach. If any-
thing ever goes wrong, an extensive
trouble -shooting guide will help you
fix it.
And people who don't understand
electronics will enjoy the best looking
picture around. Popular Electronics
said the picture on the 25" (diagonal)
screen "can only be described as su-
perb. The Black (Negative) Matrix
CRT, the tuner and IF strip, and the
vide() amplifier provide a picture equal
to that of many studio monitors..."
Everyone likes the on -screen readout
that puts the channel number into the
picture whenever you want it. When
yob change channels or touch the re-
call button, the big, bright dicits
reappear. Add the -optional clock
module and you'll see thetime as well
as the channel.
The optional wireless remote control
makes the GR-2000 even more enjoy-
able. Change channels, adjust the vol-
ume, set tint and color intensity and
turn the set on or off from across the
room. And, a touch of the Volume bar
automatically returns the digital read-
out to the screen momentarily. It's an
amazing handful of convenience.
Even if you don't havé a lot of kit -
building experience, you'll enjoy the
GR-2000. Illustrated step-by-step in-
0
structioñs, prefabricated wiring har-
nesses, transistor and IC sockets and
modular circuit boards greatly sim-
plify assembly..
See the TV the experts are talking
about. Popular Electronics summed it
all up: "In.our view, the color. TV of
the future is here-and Heath's GR-
2000 is it!"
GR-2000-the TV everyone can ap-
preciate.
Mail order price for chassis and tube,
$669.95. Remote control, $89.95, mail
order.
Cabinets
start at
$154.95,
mail
order.
(Retail
prices
slightly
higher.)
72 POPULAR ELECTRONICS
AmericanRadioHistory.Com
Christmas gift for
your list Our new
Give your scientist, engineer or stu-
dent a gift he'll use all year long.
Finger -sized keys and 8 bright 1/2" dig-
its make it easier to use than pocket
calculators. Cumulative memory and
register exchanges virtually eliminate
scratchpad work. Performs arithmetic
plus trig and arc trig in degrees
or radians, common
and natural
logs,
powers of e,
square roots,
inverses, pi
and exponential
functions.
Kit IC -2100, 4 lbs.,
mailable ..119.95*
Unique New Heathkit
AM/FM Digital Clock Radio
Our outstanding clock radio makes
even sleepy Santas happy.
Heathkit
Desktop
Electronic
Sliderule
Solves Your
Gift- Giving
Problems
_ .
;`' .,
I ' g- ..
:+^s ,t; -,;µ
12). - -- _...',. ea1iR
The electronic clock with snooze
alarm features a gentle "beep" with
adjustable volume. Or wake to the
component -quality AM/FM radio.
Standby batteries (not included) keep
the clock on time during power inter- The JK-18A teaches kids electronics
ruptions. Kit GR-1075, 10 lbs., mail- the easy learn -by -doing way. 35 excit-
able 129.95* ing projects include light meter, sound
meter, transistor radios. For safety,
it's battery
powered and
requires no
soldering.
(Batteries not
included) Kit
torrogifforsaJK-18A, 10 lbs.,
mailable ..34.95*
'N:0;N.`
- .
New Heathkit
Aircraft Strobe
A bright idea for the pilot on your list
-or for anyone who needs an emerg-
ency marine or marker light. It meets
FAR 23.1401 and
assembles easily in
just one evening. For
12 VDC neg.. ground.
With clear lens,
optional red
and red/clear
lenses available.
Kit OL-1155, 3 lbs.,
mailable ....54.95*
tab-
G?ZyGxG7
Learning's Fun With Our New
Heathkit "Electronics Workshop"
F-
New Heathkit Electronic
Clock/Timer for Car,
Boat or Plane
7.'1.1"s" z' ®
:jy 11.4
A timely gitt-
an electronic clock and a 20 -hour rally
timer, both with quartz crystal accur-
acy. Bright 1/2" -tall digits dim automa-
tically at night. 12 VDC, mounts on or
under dash. Kit GC -1093, 2 lbs., mail-
able 62.95*
Two Heathkit Electronic
Clocks with Standby Power
Two beautiful gifts-the GC -1092A is
a clock with a snooze alarm; the GC -
10920 reads the time in 6 digits, the
month and date in 4 digits. Both have
standby power to keep 'the clock on
time without the display even during
temporary power interruptions. (Bat-
teries not included.) Kit GC -1092A or
ID, 5 lbs., mailable each 82.95*
- .- -.
r..v i 6 25
Time/Alarm
Heathkit Exhaust Analyzer
Checks Your Car's Tune Up
Make everyone's Christmas whiter and
cleaner-be sure your tune up is help-
ing clean up the environment. Big 41/2"
meter reads
--
11
relative
combustion
efficiency,
,-1.--1-111. ' air -fuel
" .- ratio and
- percentage
carbon monoxide.
Kit CI -1080, 6 lbs., mailable ...59.95*
NOVEMBER 1974 75
AmericanRadioHistory.Com
Exciting new Heathkit
Christmas giving
new Heathkit
dual -trace DC-15MHz scope
,r' =aa=N,<Irouai Taco. oauuoaeoaa
vOtT5tC9
OoSalo,. KGOOC
It offers a
lot more than
just a low price
MODEL IC,aaTC J
V,,PMILE T.9[CY
FLU - ,OP u
.'V',' t Compare the features:
Dual -trace with true X -Y
capability
1 mV/cm vertical sensitivity
to ]y + over the full bandwidth
?f
np xunryry I
, r._
vOlrsiCM MM. 900f
.0ºTOft
o -
The Heathkit 10-4510 is your best
'scope buy for two good reasons-it
does more and it costs less.
Time base sweep up to 100 nsec/cm.
There's always a reference baseline,
even when there's no trigger signal.
The time base can be precisely trig-
gered at any point along the positive
or negative slope of the trigger signal.
In automatic mode, it triggers at the
zero crossing point.
Modes of display. Either channel can
be displayed as a function of time or
both can be displayed together. In
X -Y operation, channel 1 provides
horizontal deflection and channel 2
r,
Post -deflection accelerated CRT
for bright trace, fast writing
Vertical amplifier delay lines for
pulse analysis capability
Digitally controlled triggering
for exceptional stability
Typically triggers up to
45 MHz-guaranteed to
30 MHz
provides vertical deflection. There are
22 calibrated time bases from 0.2 sec/
cm to 0.1 µsec/cm. The sweep speed
is continuously variable between
switch positions. Any speed can be
expanded five times by pulling out the
control knob.
For easy calibration, a 1 volt peak -to -
peak square wave is available on the
front panel. The regulated supply op-
erates from 100 -280 -volt AC power.
Kit 10-4510, 34 lbs., mailable 549.95*
Assembled 'S0-4510, factory -wired &
calibrated!veráion of the 10-4510, 34
lbs., mailable' 750.00*
_ ;:;
,
rtt
.. : .;
_..
..
._
. .. .. Ulk .H1
New Low -Cost Heathkit
Function Generator
A true function generator, not an os-
cillator, delivers sine, square and tri-
angle waveforms from 0.1 Hz to 1
MHz. Short -proof output supplies 10
volts peak -to -peak into 50 -ohm load.
A calibrated step attenuator adjusts
from 0-50 dB (10V to 30 mV) in 10 dB
steps. A variable control provides up
to 20 dB of additional attenuation at
each step. Attenuator accuracy is ±1
dB; frequency accuracy is ±3%. Non -
linearity of the triangle waveform is
5% max., symmetry is within 10%.
Sine wave THD is 3% max. from 5-
100k Hz. Square wave rise and fall
times are 100 nsec max. 105-130 or
210-260 VAC. Kit IG-1271, 7 lbs., mail-
able 99.95*
Assembled SG -1271, factory -wired &
calibrated version of IG-1271, 7 lbs.,
mailable 140.00*
76 POPULAR ELECTRONICS
AmericanRadioHistory.Com
projects -timed for
Coming in December...
A new
generation of
Heathkit ham
radio equipment
New Heathkit SB-104 transceiver
Years ahead in design & features - the SB-104
is a complete rethinking of what a CW/SSB
transceiver should be. It utilizes the latest digi-
tal & solid-state technologies. The "104" is com-
pletely solid-state from the front end to the RF
output.
Totally broadbanded. You can switch from 3 to
30 MHz without preselector, load or tune con-
trols.
True digital readout with 6 bright digits to indi-
cate the frequency with accuracy to 100 Hz..
Mobile -ready. The SB-104 operates from 12
VDC, so it's ready to go mobile when you are.
Optional features include a plug-in digital noise
blanker and 400 Hz crystal filter for CW.
Just about the only things that aren't totally new
about the "104" are the quality and easy assem-
bly that have made Heath famous. Kit SB-104,
31 lbs., mailable 669.95*
Kit SBA -104-3, 400 Hz CW crystal filter for SB-
104, 1 lb., mailable 34.95
Kit SBA -104-1, digital noise blanker for
SB-104, 1 lb., mailable 24.95'
Kit SBA -104-2, mobile mount, 6 lbs.,
New Heathkit SB-230 1 kW
conduction -cooled linear
High -power match for the SB-104. Lowest cost
conduction cooled linear on the market. 1200
watts PEP and 1000 watts CW from less than
100 watts input. It's also rated at 400 watts in-
put for slow -scan TV and RTTY. And absolutely
silent - no blowers, no fans.
Full metering of relative power, plate current,
grid current and plate high voltage. Safety fea-
tures include microswitch interlocks for top and
bottom shells, thermal shutdown, fused cathode,
on/off switch with circuit breaker for power
transformer.
On the air in 15 to 20 hours. Fast, easy assem-
bly, then check it out with an ohmmeter - no
.alignment necessary. Kit SB-230, 40 lbs., mail-
able 319.95*
New Heathkit SB-614
station monitor scope
How clean is your signal? The bright 11/2 x 2"
screen helps you keep your rig in peak condi-
tion. Reveals a wide variety of operating prob-
lems - nonlinearity, insufficient or excessive
drive, carrier or sideband suppression problems,
regeneration and key clicks. Monitors AM, SSB
and CW signals up to 1 kW from 80 to 6 meters.
Kit SB-614, 17 lbs., mailable 139.95*
-
mailable 34.95' Ii1.1 .
, . a `P .
" I43012^ 31
New Heathkit 5 -Function
SB-634 station console
Five accessories in one - a 24 -hour 6 -digit
electronic clock, a ten-minute digital ID timer
with visual and/or audible alarms, RF wattme-
ter, SWR bridge, hybrid phone patch with man-
ual and VOX controls. Kit SB-634, 14 lbs., mail-
able 179.95'
New Heathkit SB-644 remote VFO
Designed exclusive for SB-104, it provides the
ultimate in multi -mode operation with two crys-
tal sockets for fixed frequencies. No modifica-
tions - just plug the VFO into the "104" and go
- VFO frequency even reads out on thé 104's
digital display. Kit SB-644, 10 lbs.,
mailable 119.95*
New Heathkit Fixed station
AC power supply
Powers the SB-104 from 120 or 240 VAC. So-
phisticated regulation assures almost no change
in voltage from no load to full load. Entire sup-
ply fits inside SB-604 speaker cabinet. Kit HP -
1144, 28 lbs., mailable 89.95*
New Heathkit SB-604
station speaker
fi 'JO i Response -tailored to SSB
and designed to match
the SB-104. Large enough to
house HP -1144 AC power supply.
Kit SB-604, 8 lbs., mailable ....29.95*
Ua .
AAnvjl
r-,
HEATHKIT ELECTRONIC CENTERS -
Units of Schlumberger Products Corporation
Retail prices slightly higher.
ARIZ.: Phoenix; CALIF.: Anaheim, El Cerrito, Los
Angeles, Pomona, Redwood City, San Diego (La
Mesa), Woodland Hills; COLO.: Denver; CONN.:
Hartford (Avon); FLA.: Miami (Hialeah), Tampa;
GA.: Atlanta; ILL.: Chicago, Downers Grove; IND.:
Indianapolis; KANSAS: Kansas City (Mission); KY.:
Louisville; LA.: New Orleans (Kenner); MD.: Balti-
more, Rockville; MASS.: Boston (Wellesley);
MICH.: Detroit; MINN.: Minneapolis (Hopkins);
MO.: St. Louis (Bridgeton); NEB.: Omaha; N.J.:
Fair Lawn; N.Y.: Buffalo (Amherst), New York City,
Jericho, L.I., Rochester, White Plains; OHIO: Cin-
cinnati (Woodlawn), Cleveland, Columbus; PA.:
Philadelphia, Pittsburgh; R.I.: Providence (War-
wick); TEXAS: Dallas, Houston; WASH.: Seattle;
WIS.: Milwaukee.
r
REAM:;
rrÁ ,
',z a1s
Heath Company, Dept. 10-11
Benton Harbor, Michigan 49022
Send for your FREE 1975 catalog today.
Please send my free 1975 Heathkit Catalog.
Please send the merchandise checked below. I've
enclosed $ _, plus shipping, in payment.
GR-2000 Color TV
Q GRA-2000-1 Digital
clock module
GRA-2000-6 TV remote
control
IC -2100 Calculator
CI -1080 Exhaust analyzer
GR-1075 Digital
clock radio
GC -1093 Digital car
clock/timer
JK-18A Junior electronics
workshop
Q GC -1092A Digital clock
with snooze alarm
Q GC -1092D Digital clock
with date display
10-4510 Oscilloscope (kit)
Q SO -4510 Oscilloscope
(assembled)
IG-1271 Function
generator (kit)
HEATH
hlumberger
SG -1271 Function
generator (assembled)
SB-104 Transceiver
SB-104-1 Noise blanker
SB-104-2 Mobile mount
SB-104-3 CW crystal filter
D SB-230 1 kW linear
SB-614 Monitor scope
SB-634 Station monitor
p SB-644 Remote VFO
HP -1144 AC power supply
SB-604 Station speaker
Name
Address
City State 7ip
'Mail order prices, FOB factory
Prices and specifications subject to change without notice. CL -541
L
NOVEMBER 1974 CIRCLE NO. 5 ON READERS SERVICE CARD 77
AmericanRadioHistory.Com
COMPUTER TERMINALS ARE COMING
THE sales and complexity of elec-
tronic calculators seem to be
rising exponentially. Practically every
month, new models appear with more
functions available. Some of the new
ones are more like mini -computers
than calculators.
Where will it all end? Someday,
each of us will probably have his own
full-blown computer. For the foresee-
able future, however, such a computer
would be a trifle large for the average
home; and the price would be out of
reach for almost everyone. But there is
a way of having the use of a full-blown
computer without buying your own.
All you need is a "computer terminal."
A computer terminal looks like a
desk calculator, has a typewriter
keyboard with a few extra keys, and is
equipped with alphanumeric readout.
The terminal shown in the photo is
typical of those now being made avail-
able at reasonable cost. The input/
output connections to the terminal are
made through some form of conven-
tional telephone -line coupler. For the
unit shown here, the coupling is made
by dropping the phone into a special
cradle.
To operate a terminal, the user sim-
ply dials his local time-shared
computer company (usually found in
the Yellow Pages) and places the
phone in the cradle. The remote com-
puter then "answers" the phone; and
after the terminal operator enters his
private billing number and the
Computer verifies it, the operator is
signalled to start his entry. What can
the operator do? Just about anything
of which the expensive computer on
the other end is capable-which is
quite a bit.
Since the computer is expensive,
operating time costs would be very
high if it were not for the use of "time-
sharing" techniques. This means that
a number of terminals are using the
same computer but sharing its time.
The computer switches from one ter-
minal to another so fast that it appears
that each terminal is the only one
using the computer. This lowers the
user price to between $9 and $30 per
month installation fee plus anywhere
from $2 to $8 per hour of actual com-
puter time. The user also pays conven-
tional telephone rates for the use of
BY LESLIE SOLOMON
Technical Editor
the line, just as he would if he were
making á conventional call.
It might appear that the hourly use
charge is high. However, if a problem
is laid out first, it takes very little time
for it to be typed in; and then the an-
swer should return within seconds. A
lot of information can pass through
such a system in a couple of minutes.
Then, the time used is cumulative.
That is, the user pays only for the ac-
cumulated computer time -a couple
of minutes here, a couple of minutes
later, etc. The system does not have to
be operated for an hour at a time.
What can a computer do for you?
Obviously it can provide a complete
household or business accounting
system in which all purchases, sales,
etc., are broken down into various
areas for tax purposes. A record of all
financial statements, income, ex-
penses, material, etc., is kept in the
electronic files. With an available
memory of up to 100,000,000 words,
quite a bit of information can be stored
for future recall by the customer.
How good is security? Can some
outsider get a look at your private
files? Precautions are generally taken
to prevent unauthorized readout.
Each customer has a private entry
code that he alone can use to gain
entry to his portion of the computer.
This private code is never displayed on
the alphanumeric readout so it re
mains a secret even if someone is
watching the operator at his console.
Some time-sharing companies have
special "programs" for their sub-
scribers. Some companies, for exam-
ple, specialize in engineering areas,
supplying subscribers with a list of
programs available. The program
might be a complete analysis of a par-
ticular problem, and all you do is insert
your own numbers. You do not have to
be familiar with the mathematics in-
volved; the computer takes care of
that. For example, assume a transistor
amplifier is to be designed or a band-
pass filter using an op amp is needed.
When you call the program, the termi-
nal readouts will "ask" certain ques-
tions regarding input, voltages, stage
gain requirements, output desired,
and so forth. Once you insert your re-
quirements in answer to the comput-
er, your circuit will be designed in
seconds, with all components iden-
tified. It is like having an engineering
textbook come to life, solving all the
problems and supplying all the an-
swers.
There are educational programs for
children in which the computer takes
on the role of teacher. Children can
learn math or other subjects and ask
all the questions they wantfrom a
teacher having infinite patience. The
computer will "talk back" when the
student does something wrong, ex-
plain the problem, or give the correct
answer.
There are also "game" programs in
which various sports or games can be
played between the computer and the
operator. This is a powerful learning
tool for students and an intellectual
exercise. There will be programs in
almost every area; and, as the library is
expanded, notification will be sent to
each subscriber.
What about cost? The MITS Com-
puter 256 terminal is $595, complete
with the acoustic coupler. This par-
ticular terminal will store 256 charac-
ters with expansion to 1026. Options
to expand up to 3 pages are available.
An auto -transmit feature allows the
user to transmit data or program ma-
terial line -by-line instead of typing it
directly into the computer, thus saving
actual computer use time. The termi-
nal also has a tape play/record feature
that gives it a virtually unlimited mem-
ory capability. Almost any type of tape
recorder can be used.
If you already have a digital comput-
er, a hard wire connector is provided
for direct connection to your own
computer. If you don't own a comput-
er, this connector will be used for
some future add-on features to further
expand the terminal. .._; _
AIMIIIMIRIa ' :-y I,7, ,
' ' _
!1'.«R_`:._ -4° n-,,-Fw., .,- ..
' _:;0
u,W I THE MITS COHTER Q36 .u'
u - --- . ...,.
i Me. e. Ma ea t all WO
t:W2 i r¿J 0111111,10 cáo .: ..n at
The MITS Cotnter 256.
POPULAR ELECTRONICS
78
AmericanRadioHistory.Com
ENGLISH
-LANGUAGE SHORTWAVE BROADCASTS FOR NOVEMBER 197.4 TO FEBRUARY 1975 by Roger Legge
TO EASTERN NORTH AMERICA
(If Standard Time is restored, EDT times are one hour earlier than listed
except the Melbourne 7:15 a.m. transmission.)
TIME -EDT TIME -GMT STATION QUAL* FREQUENCIES, MHz
7:00-8:15 a.m. 1100-1215 London, England G 11.905, 15.07
7:00-9:00 a.m. 1200-1400 **VOA,
Washington, U.S.A.
G 6.185, 9.565
7:15-8:45 a.m. 1115-1245 Melbourne, Australia G 7.295, 9.58
7:30-8:00 a.m. 1130-1200 Jerusalem, Israel F 12.025, 15.13
8:00-8:15 a.m. 1200-1215 Tokyo, Japan F 5.99
8:00- 8:55 a.m. 1200-1255 Montreal, Canada G 5.97, 11.825
9:00-9:30 a.m. 1300-1330 *"Bucharest, Romania F 15.25.
9:15-9:45 a.m. 1315-1345 Berne, Switzerland G 15.14
10:00-10:30 a.m. 1400.1430 Helsinki, Finland G 15.185
Stockholm, Sweden G 17.71
10:30 a.m.-12:15 p.m. 1430-1615 London, England G 17.84 (via Ascension Is.)
4:00-4:45 p.m. 2000-2045 Jerusalem, Israel F 7.395, 9.495, 9.815
5:15-7:00 p.m. 2115-2300 London, England G 5.975, 9.58, 15.26
5:30-6:50 p.m. 2130-2250 Hilversum, Holland F 9.715, 11.73 (Sun.: Dutch)
6:30-8:20 p.m. 2230-0020 Johannesburg, S. Africa G 9.585, 9.695, 11.90, 11.97
6:55-7:15 p.m. 2255-2315 Brussels, Belgium F 6.055
7:00-8:30 p.m. 2300-0030 Moscow; U.S.S.R. G 5.94, 7.15, 7.205, 9.685
7:45-8:45 p.m. 2345-0045 Tokyo, Japan P 15.27, 15.445 -
8:00-8:30 p.m. 0000.0030 Tirana, Albania G 7.065, 9.78
8:00-9:00 p.m. 0000-0100 Peking, China F 9.94, 11.945
Sofia, Bulgaria F 6.07, 9.70
8:00-10:00 p.m. 0000.0200 ""VOA,
Washington, U.S.A.
G 6.13, 9.65, 11.83
8:30-9:00 p.m. 0030.0100 Stockholm, Sweden P 6.00
8:30-9:00 p.m. 0030-0100 Kiev, U.S.S.R. G 5.94, 7.15, 7.205
Mo/Th/Sa Tu/Fr/Su
8:30 p.m. -3:00 a.m, 0030-0700 HCJB, Quito, Ecuador G 5.965, 9.56, 11.915
8:40-9:00 p.m. 0040-0100 Brussels, Belgium F 6.055
9:00-9:15 p.m. 0100.0115 Vatican City F 5.995, 9.605
9:00-9:20 p: m. 0100.0120 Rome, Italy P 6.01, 9.575
9:00-9:30 p.m. 0100-0130 Budapest, Hungary P 6.00, 9.833
9:00-9:45 p.m. 0100-0145 Berlin, DDR P 5.955, 9.73
Madrid, Spain F 6.065
9:00-10:00 p.m. 0100-0200 Montreal, Canada G 6.085, 9.755
Peking, China F 7.12, 9.78 (via Tirana)
Prague, Czechoslovakia F 5.93, 7.345, 9.54
9:00-11:00 p.m. 0100.0300 Melbourne, Australia P 11.97, 15.32
9:00-11:30 p.m. 0100.0330 London, England G 5.975, 7.325, 9.51
9:00-11:30 p.m. 0100-0330 Havana, Cuba F 11.725, 11.93
9:00 p.m. -1:00 a.m. 0100.0500 Moscow, F 5.94, 7:15, 7.165, 7.205
9:30-9:55 p.m. 0130-0155 Tirana, Albania F 6.20, 7.30
Vienna, Austria P 6.155, 9.77
9:30-10:30 p.m. 0130-0230 Bucharest, Romania P 5.99, 9.57
tG
TIME -EDT TIME -GMT STATION QUAL* FREQUENCIES, MHz
9:30-10:50 p.m. 0130-0250 Cologne, Germany F 6.04, 6.075, 9.545, 9.69
9:4510:15 p.m. 0145-0215 Berne, Switzerland F 5.98, 6.12, 9.535
10:00-10:45 p.m. 0200.0245 Lisbon, Portugal F 6.025
10:00-11:20 p.m. 0200.0320 Hilversum, Holland G 6.165 (via Bonaire)
10:00-11:30 p.m. 0200-0330 Cairo, Egypt P 9.475
10:30-11:00 p.m. 0230-0300 Beirut, Lebanon P 9.66
11:00 p.m.12 mdt 0300-0400 Buenos Aires, Argentina F 9.69 (Mon. -Fri.)
Peking, China F 7.12, 9.78 (via Tirana)
Prague, Czechoslovakia F 5.93, 7.345, 9.54
TO WESTERN NORTH AMERICA
(If Standard Time is restored, PDT times are one hour earlier than listed.)
TIME
-PDT TIME -GMT STATION QUAL* FREQUENCIES, MHz
7:00-9:00 a.m. 1400-1600 **VOA G 6.185,9.565
Washington, U.S.A.
8:00-8:15 a.m. 1500-1515 Tokyo, Japan G 5.99
4:00-5:30 p.m. 2300-0030 London, England G 6.175, 9.74 (via Canada)
5:00-7:00 p.m. 0000-0200 London, England F 9.51, 15.26 (via Ascension Is.)
5:30- p.m.-12.mdt 0030-0700 HCJB, Quito, -Ecuador G 9.56, 11.915
6:00-7:00 p.m. 0100.0200 Peking, China G 9.94, 11.945
6:00-8:00 p.m. 0100-0300 Melbourne, Australia G 11.97, 15.32, 17.795
6:00-8:00 p.m. 0100.0300 Moscow, U.S.S.R. G 12.05, 15.18 (via Khabarovsk)
6:30-7:30 p.m. 0130-0230 Tokyo, Japan G 15.235, 15.445, 17.825
7:00-8:50 p.m. 0200-0350 Taipei, Taiwan F 11.86, 15.125, 17.72
7:00-9:15 p.m. 0200-0415 London, England F 9.51, 15.26 (via Ascension Is.)
7:30-8:00 p.m. 0230-0300 Stockholm, Sweden P 6.045
8:00-8:30 p.m. 0300-0330 Seoul, Korea F 11.925
8:00-10:00 p.m. 0300-0500 Peking, China G 15.06, 17.735, 17.825
8:30 p.m. -12:30 a.m. 0330-0730 Moscow, U.S.S.R. G 11.72, 12.05,15.10 (via Khabarovsk)
9:00-9:15 p.m. 0400-0415 Tokyo, Japan G 15.105
9:00-10:55 p.m. 0400-0555 Montreal, Canada G 6.135, 9655
9:30-10:00 p.m. 0430-0500 Berne, Switzerland P 5.98, 9.75
9:35-10:55 p.m. 0435-0555 Cologne, Germany G 6.085, 9.605 (via Canada)
10:00-11:20 p.m. 0500-0620 Hilversum, Holland G 6.165, 9.715 (via Bonaire)
11:00-11:15 p.m. 0600-0615 Tokyo, Japan G 9.505
11:00 p.m. -12 mdt 0600-0700 Buenos Aires, Argentina F 9.69 (Mon. -Fri.)
11:30 p.m. -1:00 a.m. 0630-0800 Havana, Cuba F 9.525
*Reception quality (Virginia location, Collins Communications Receiver, L antenna): G -good, F -fair, P -poor
Reception quality of Western North America broadcasts is expected reception in California.
** Not intended for North America, but receivable satisfactorily.
Reception of many evening broadcasts are expected to be fair or poor during the winter months, due
to low MU F's (Maximum Usable Frequencies), associated with the winter low of the 11 -year sunspot cycle.
AmericanRadioHistory.Com
iii AcrisLim\\
11..".11111LZ
CILIPI\O"' ..
\\LW Dapo
C.C. C.
"SECRET" SW STATIONS
S winter approaches, static on
the 2 -3 -MHz band declines, al-
lowing us to hear some well-known
broadcasters. Low -powered stations
in Latin America, Africa and the
Pacific inhabit the 120 -meter tropical
band (2300-2495 kHz); high-powered
outlets in China and both Koreas
spread beyond this range.
Usually closer but offering no less a
challenge to DX are the secret short-
wave stations! So secret are they that
even the people operating them are in
the dark (or if they are aware, they
hope no one will notice).
SAVE!
MONEY TIME FREIGHT
QUALITY STEREO EQUIPMENT
AT LOWEST PRICES.
YOUR REQUEST FOR QUOTA-
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FACTORY SEALED CARTONS-
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SAVE ON NAME BRANDS LIKE:
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SONY FISHER
AND MORE THAN 50 OTHERS
BUY THE MODERN WAY
BY MAIL-FROM
6 illino'v audio
Department 217S
12 East Delaware
Chicago, Illinois 60611
312-664-0020
CIRCLE NO. 20 ON READERS SERVICE CARD
80 POPULAR ELECTRONICS
DX
Listening
By Glenn Hauser
gramming just about has to be har-
monic!
When you suspect a harmonic, di-
vide the measured frequency by 2 or 3
to see if its fundamental matches up
with a known station. Then tune to the
fundamental frequency; chances are
you won't hear it there, but if you do, it
should be under entirely different
conditions of interference, fading and
strength. Such a check will prove that
you are receiving a transmitted har-
monic, propagated on the frequency
where you find it.
Don't give up if at first you don't
succeed; the selection of harmonics is
continually changing as different sta-
tions tweak their traps. Do report your
harmonic DX to other enthusiasts, but
not to the station! Once they learn
their harmonic is getting out, they just
might be moved to eliminate it perma-
nently. Let's keep the secret.
DX Monographs. The National
Radio Club has become quite a pub-
lisher, not only for its members but for
a wider readership. Over the past few
years, NRC has published many tech-
nical articles about antennas suitable
for mediumwave reception. Now,
they're compiled in the NRC Antenna
Book, the first of many reprint books
to be issued. You'll find everything
from the portable ferrite rod to the
mile -long Beverage wave antenna, in-
cluding much ado about loops: direct
coupled, degenerate, balanced, un-
balanced and box. The 60 -page book
is $2.25; and many other individual ar-
ticle reprints are available too. For a
list, send an SASE to NRC, Box 127,
Boonton, NJ 07005.
We're talking about harmonics of
mediumwave (standard AM broad-
cast) stations. By combining a good
antenna and receiver system with lots
of diligent delving into the residual
noise level, you too can intercept
these secret flea -powered broadcasts.
Even in the central USA, the great
majority of harmonics heard originate
in Latin America; this speaks highly
for the harmonic -suppression stan-
dards of the FCC, probably the most
rigid in the world.
A harmonic is not just any off -
frequency reception of a station. It
must be an exact integral multiple of
the fundamental. Second harmonics
(twice the fundamental) are by far the
most common, since progressively
smaller amounts of power are radiated
as harmonic numbers go up.
The way to DX harmonics success-
fully is to know the 1.6 -3.2 -MHz band
-so you can quickly eliminate every-
thing that isn't a DX harmonic. If you
live near a nighttime MW station, you
probably can't help but hear its sec-
ond and/or third harmonic. Wheth-
er transmitted, or the result of receiv-
er overload on the fundamental, local
harmonics are of no DX interest.
If you live near two or more night-
time MW stations, their mixing prod-
ucts may be audible. You can predict
where most of them will show D
summing each pair of fundamental
frequencies, and by doubling one, and
then subtracting another, in all possi-
ble combinations.
You can also eliminate any trans-
mission not consisting of program-
ming, such as hams, LORAN, radiolo-
cation beeps, time signals, ship and
shore, military nets, aircraft, RTTY,
etc., etc.
This leaves the legit 120-m broad-
casters. In the evenings, you'll hear
mostly Venezuela, Brazil and Haiti;
and Mexico and Guatemala fight it out
only on 2390 kHz. Any other pro -
DX Courtesy. Back in the heyday of
radio, many MW stations went on the
air in the wee hours with special pro-
grams for DX listeners. The practice
still continues, thanks to a small band
of enthusiasts in the NRC, Interna-
tional Radio Club of America, and
Newark News Radio Club-the clubs
most involved in MW DX. Each has its
own "Courtesy Programs Committee"
(CPC), but they coordinate their ef-
forts to avoid duplication. Most CPC
broadcasts occur on Monday morn-
ings during the winter season, when
24 -hour stations take a few hours off.
But the tests are scheduled for the
most open "window," as determined
from the NRC Log's schedule section
and continually revised "condition of
frequencies" lists. Each club pub-
lishes calendars of upcoming spe-
AmericanRadioHistory.Com
cials. The astute late -night MW DX'er
can add stations and states he might
never hear any other way. It's all ar-
ranged by volunteers, which means
there would be more such DX specials
if there were more volunteers (hint,
hint).
Europe on Your Clock Radio?
Trans -Atlantic (TA) MW DX usually
peaks during October and November;
the exact dates depend on solar varia-
tions. Several days 'of low A -indices
(below 10) broadcast on WWV at 18
past the hour signal optimum condi-
tions. You'll have a much better
chance to hear Europe on the BCB if
you're in the eastern half of the conti-
nent. Most European channels are
"split" between ours, so powerhouses
of 300 to 1200 kW can even come
through an 'all-American five' if you
tune just right. The band usually
opens from the top downward, so
check 1586 for Wést Germany, 1554
for France and 1466 kHz for Monaco
just after local sunset and again
around midnight. But watch out for
buzzes from nearby TV sets which also
show up on split frequencies. Later on
in November or December the so-
called "Midwinter Anomaly" puts a
damper on this high -latitude MW DX.
Pings & Bursts. Before we go, some
tips for vhf people. November and De-
cember are among the best months
for meteor scatter DX'ing. High -gain
antennas on FM and TV will reveal
'pings' every few minutes on just
about any morning; the diurnal peak
of MS is at 6 a.m. local mean time.
Chances for more strong, long 'bursts'
are markedly greater during the
meteor showers: Orionids, October
18-23; Leonids, November 14-18; and
best of all, the Geminids, December
10-14. If you're lucky enough to catch
a burst during a test pattern or ID
break, you've bagged a new station
-even if the reception only lasts a few
seconds. This happens more often
than you might think. "If you're not
equipped for this esoteric signal
snatching, you can still look out for
winter sporadic E openings; check the
lowest open TV channels each even-
ing, especially in December and
January. For vhf DX'ers in Gulf coastal
states, this is the time for thousand -
mile uhf hauls or trans -Gulf Mexican
vhf. You'll find much more on televi-
sion DX'ing in the POPULAR ELEC-
TRONICS 1975 COMMUNICATIONS
HANDBOOK, available soon.
NOVEMBER 1974
Plug in...wire
t.
S -
PAT. PENDING
without soldering
for as little as $OO
New Continental Specialties QT
UNIQUE NEW SOCKETS® and BUS STRIPS
SNAP/LOCK DESIGN", offer expanded, flexible bread-
boarding without shorts or
>r ,. burnt fingers. Simply SNAP/
LOCK together as many
QTs as you need and you
'11 can test ICs, transistors,
resistors, capacitors and
. more. Just plug-in, connect
with solid #22 AWG hook-
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AmericanRadioHistory.Com
MAC'S SERVICE SHOP
The Simplest
Test Gear
é i HEY, Mac, what are you do-
ing with the tattle lights?"
Barney asked his employer, who was
examining several small objects
spread out on the service bench.
"Taking them with me on vacation,"
Mac replied. "Some of the folks in
Florida we visit are sure to say, 'Mac,
our electric or electronic what-
chamacallit isn't working. Wonder if
you'll look at it.' These lights will let me
find anything simple, which is all I in-
tend to tackle on vacation. Actually,
it's amazing what a fellow can do with
some simple, rugged, inexpensive test
lights and a little gray matter."
"For instance?"
"Well, take this Ne-O-Lite Test Light
put out by GC Electronics, a division of
Hydrometals, Inc., Rockford, Ill. It car-
ries Audiotex catalogue No. 30-245 or
Calectro No. H3-452 and sells for just
under a buck. As you can see, it con-
sists of a special two -inch -long, red,
high -impact plastic socket carrying a
neon bulb protected by a tough clear
plastic cone in one end. A current -
limiting resistor of-I'd guess-about
200,000 ohms is contained in the
socket, and red and black flexible,
sharp -pointed leads come out the bot-
tom. The lamp glows with any voltage
from 90 to 550 volts, ac or dc. The
higher the voltage, the brighter the
glow.
"The neon lamp itself has almost in-
finite resistance until the contained
gas is ionized by over 90 volts. Until
then, there's no voltage drop across
the series resistor, so the full voltage
across the test leads is applied to the
lamp. Once the gas is ionized by a
voltage in excess of 90 V, current
through the lamp and series resistor is
a function of the voltage across the
leads, but it never exceeds 3 mA, even
with the full 550 volts applied.
"What can you do with it?"
"A zillion things. If one lead is at-
tached to a spark plug of a running
motor, a bright flash will indicate a
good plug; a dim flash, a fouled plug;
and no flash, a dead plug. Hold on to
By John T. Frye, W9EGV
one test lead and probe the two sides
of a 120 -volt outlet receptacle with the
other. When you touch the 'hot' side of
the line, the lamp will glow. If a device
controlled by a wall switch will not
turn on and you don't know if the trcu-
ble lies in the device or the switch, turn
the switch on and bridge the test lamp
across the switch terminals. If the
lamp glows, the switch is bad. Do the
same thing to locate a blown fuse.
With a device on the fused line
switched on, check across the fuse
with the lamp. If it glows, the fuse is
open. Alternately, you can check from
the grounded side of the line or the
cabinet of the fuse box to the output
sides of the fuses, one at a time. Fail-
ure of the lamp to glow with full 120-V
brilliance will indicate the bad fuse.
"This little sketch shows how the
test lamp can be used for a continuity
IRON
EXTENSION
CORO
TESTER
indicator. Plug an extension cord into
a wall receptacle and locate the hot
side of the cube tap on the end of the
cord. Plug one lamp lead into this side.
Now plug one prong of the cord of the
device you want to test for continuity
into the other, grounded, side of the
cube tap. Touch the free lamp test lead
to the free prong of the line cord of the
device. A glow of the lamp indicates
continuity.
"The test light will indicate the pres-
ence of leakage current. As you know,
one side of the 117 -volt line is
grounded. If there's current leakage
from the hot side of the line to the case
of a device, say a hedge -trimmer, elec-
tric drill, refrigerator, dishwasher, etc.,
a person touching the device while in
contact with the ground or a grounded
device may receive a severe and
perhaps fatal shock. With a clip lead,
connect one side of the test lamp to a
good ground, such as a water faucet,
and touch the other lead to the case of
the device being tested while the de-
vice is operating. Reverse the plug of
the device in the wall socket and test
again. If the lamp glows in either case,
you know there'ssome leakage. It may
not exceed 0.5 mA through 1500 ohms
of noninductive resistance shunted by
0.15 µF, which represents the average
impedance of the human body and the
current is considered permissible for
most devices; but if the lamp glows at
full 120-V brilliance, you can be sus-
picious. In all the devices I checked at
home, only the electric drill, some fif-
teen years old, lit the light dimly."
"What's this thing?" Barney asked,
picking up a small round plastic object
with three prongs on one end to fit a
standard 15-A, 120-V grounding re-
ceptacle.
"That's a GT-20 'Grounded Outlet'
Tester made by Alco Electronic Prod-
ucts, 1551 Osgood Street, North An-
dover, Mass. 01845. It sells, in single
lots, for $7.95 and reveals instantly if a
receptacle into which it is plugged has
current available and is properly and
safely wired. Note the three little round
windows in the end. Two of them,
labelled NEUTRAL and POWER, are
amber, and the bottom one, labelled
DANGER, POLARITY is red. When the
GT-20 is plugged into a grounding re-
ceptacle, one or more of the lights be-
hind the windows light if power is
available at the socket. If the socket is
correctly wired, the two amber win-
dows glow. Any other combination of
lights indicates a potentially danger-
ous receptacle that is improperly
wired or has a broken connection.
"What's inside the thing?"
"Not being like the little boy who cut
open his drum to find what made the
noise, I didn't take it apart to see; but
I'd guess there are three neon lamps
with accompanying current -limiting
resistors, each wired between a pair of
prongs. Can you figure out which
lamp is wired between which prongs
to produce the conditions shown in
the little charts?"
"Child's play!" Barney scoffed.
"Will it work on 2 -hole outlets?"
"The Code requires that, in all new
construction, only grounding recep-
tacles may be installed. If you replace
a defective receptacle in an existing
88 POPULAR ELECTRONICS
AmericanRadioHistory.Com
installation, the new one must be the
grounding type if you can effectively
ground it. If this is difficult or impossi-
ble, the receptacle may not be of the
grounding type. You don't want a re-
ceptacle with a dummy grounding
orifice that seems to promise but does
not actually provide grounding of a
device with a 3 -wire cord plugged into
it. You can use the GT-20 as a 2 -wire
tester by using an adapter plug with
the pigtail fastened to the outlet box
by placing it under ametal screw hold-
ing the receptacle plate in place. If the
red light of the GT-20 glows when the
adapter is plugged in, reverse the
position of the two blades. If the red
light still glows, a ground fault is indi-
cated and repairs should be made.
The only fault the GT-20 will not reveal
is switching of the neutral and ground
wires, since both are normally at
ground potential; but this very rarely
occurs.
"How come you've got two neon
test lights?"
"I haven't. That one you're holding
looks like the H3-452, but it is really a
Calectro No H3-454. About the only
difference you can see is that the plas-
tic is blue instead of red. It is called a
Lo -Volt Test Light and will light with 5
to 50 volts ac or dc. If you look closely;
however, you'll see the bulb in the end
is a filament type instead of neon. 'I've
found this filament will glow dimly
with 3 volts across the test leads while
it is drawing 18 mA. At 12 volts ,the
filament is a very bright yellow and
draws 45 mA. This goes to 11Q mA at
50 volts, and the filament is incandes
cent white. Filament resistance goes
from 80 ohms cold to 550 ohms at 50
volts, which explains the wide range of
lighting voltage.
"The Lo -Volt Tester is especially
useful in trouble -shooting auto elec-
trical problems. Failure to light across
the battery terminals indicates a dead
battery. If the battery is OK, you can
trace the voltage from it right to an
accessory that fails to work. With the
accessory turned on, the lamp will
light across a defective switch or fuse.
It will also light across a high resis-
tance connection, say a battery cable
connection or starter solenoid con-
tacts, when the starter is actuated and
tries to draw heavy current through
the connection. By connecting ,the
lamp between an insulation -piercing
darning needle and ground, you can
pinpoint a break in a wire. The lamp
will indicate generator output. 'It can
be used with the 12 -volt battery to in-
dicate continuity, since it will glow ;R
with any series resistance from 500
ohms down.
"The Lo -Volt Tester is also useful in
the home for checking out low -voltage
door -bell circuits, electric trains, and I°
slot cars. With a 9 -volt transistor bat-
tery, it can be used as a continuity in-
dicator. With a little practice, you can
also use it to indicate the condition of
6- and 9 -volt batteries."
"Well," Barney said as Mac paused,
"that only leaves this little red bulb no
bigger than a match head."
"That's a brand new RLC-400 Bat-
tery Status Indicator just released by
Litronix, Inc., 19000 Homestead Road,
Cupertino, Calif. 95014. It sells for a
dollar at Litronix representatives all
over the country. A GaAsP LED and a
voltage -sensing IC are both packed
inside that itty-bitty T-1 lamp package
designed to warn of imminent battery
failure in cameras, tape recorders,
calcualtors, and similar battery -
powered equipment. The LED lights
brightly at 3 V, glows dimly at 2.5 V,
and is completely dark at 2 V. It drawl
about 300 microamperes at 2.5 V, 8 mA
at 3 V, and 20 mA at 4 V. Five volts,
forward or reverse, is maximum.
"To use the RLC-400 with higher
voltage batteries presented a bit of a
problem. A series resistor subjected
the device to a high turn -on voltage
and separated on on -off points too
much. A zener took care of the first
problem, bLt the on -off points were
only a half -volt apart. I finally worked
out the circuit shown to let me use the
6.8V ORLC-400
4701E
X +
ZENER
I2V -9V
Y-
RLC-400 with any battery voltage and
make the on -off span proportional to
that voltage. With the values shown, 3
V appears across the LED with 12 V
across points X and Y. There is 2.5 V
across the LED with 9 V at X -Y. Other
zeners and resistor values can ac-
commodate other battery voltages
and provide any desired span between
new and discard battery voltage. This
little lamp has a lot of exciting pos-
sibilities," he concluded.
"You know," Barney mused, "a
knowledgeable guy can do a lot with
comparatively simple equipment."
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CECLE NO. 14 ON READERS SERVICE CARD
89
NOVEMBER 1974
AmericanRadioHistory.Com
-1111AF/ Solid State
USEFUL CIRCUITS FOR FIELD EFFECT TRANSISTORS
THOUGH more versatile than bipolar types, except in
some power applications, field effect transistors
-FET's-have never been overly popular with experi-
menters and hobbyists. True, FET's have been featured in
magazine construction articles from time to time, and
there have even been several.project booklets published
featuring FET circuits but, somehow, these devices have
never really "caught on."
There are probably several reasons for the FET's lack of
popularity. One may be the paucity of application data
compared to what is available on bipolar devices. Another
reason, perhaps equally important, may be the somewhat
confusing situation regarding types. FET's are manufac-
tured in two general categories and six major sub-
categories, in addition to variations relating to electrical
specifications. The two broad categories are insulated
gate types, or IGFET's, and junction types, or JFET's. Since
many insulated gate FET's are manufactured using MOS
technology, these are often designated MOS-FET's, while
junction FET's frequently are identified simply as FET's
(without the J prefix). But there's more. IGFET's may be
manufactured for use in either depletion or enhancement
modes, each of which has its own technical advantages,
but which may require somewhat different application
techniques, depending on the circuit in which it is used.
Finally, both IGFET's and junction FET's are available as
either n -channel or p -channel devices. These are analo-
gous to npn and pnp bipolar transistors, in that they may be
used in similar applications, but require opposite dc
polarities.
Poor availability may be another reason for the FET's
lack of popularity. The first low-cost experimenter's tran-
sistor, the famous Raytheon CK722, was a bipolar device.
FET's, on the other hand, were comparatively late arriving
on the scene and, by the time inexpensive FET's were
available, a mass of application literature and project arti-
cles had been published featuring bipolar devices, result-
ing in a much larger demand by users for these types. As a
result, suppliers offering general-purpose semiconductor
devices today may list scores of different bipolar transis-
tors but maybe only from one to a half -dozen FET's. As of
the present writing, for example, there are only five differ-
ent FET's listed in Sylvania's ECG line, two types in RCA's
SK line, eight in Motorola's HEP line, three in GC
Electronic's Calectro line, and one in Radio Shack's
Archer line. There are many other types of FET's in produc-
tion of course, but the prospective user will not find these
in a general line on a self-service sales rack. Instead, he'll
have to buy them across the counter, specifying
manufacturer's name and type number, and perhaps even
seek out a broad line or industrial electronics distributor
By Lou Garner
stocking the units needed. In extreme cases, the user may
find it necessary to order specific devices from a large
mail-order or semiconductor specialty house.
The FET has been called the"semiconductor equivalent
of the vacuum tube." This analogy is pretty close to the
truth. The FET offers high input and output impedances. It
is a voltage, rather than a current, amplifier. It can be
self -biased via a source resistor and its characteristics
curves are quite similar to those of a pentode vacuum tube.
The basic FET has three terminals-gate (G), source (S)
and drain (D). These correspond, generally, to the base,
emitter and collector of a bipolar transistor, or to the grid,
cathode and plate of a vacuum tube, respectively.
The IGFET (or MOSFET) has an extremely high input
impedance. The junction FET also has a high input impe-
dance, although not nearly as great as the IGFET; but, from
an experimenter's viewpoint, it is by far the easier device to
use in practical circuits. Except for those types with inter-
nal protection, the IGFET (MOSFET) requires special
treatment. It is particularly susceptible to damage from
static charges or transient voltages applied to its gate
electrode, even during the simple processes of handling
and installation. Some types, in fact, are supplied wrapped
in metal foil or with their leads shorted by a metal eyelet or
spring to prevent accidental damage. The short can be
removed safely only after the device is installed in its cir-
cuit. Perhaps the best way to become familiar with the FET is
to try the device in a few practical projects. Several useful
and easily constructed junction FET circuits are illustrated
in Figs. 1 and 2. These were adapted from a FET applica-
tions bulletin published several years ago by Siliconix, Inc.
X TAL
G
Fig. 1. Useful FET circuits: (A)
Crystal oscillator; (B) Tone control.
v-
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60-120yH
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pF
R2
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NOTE: ALL CAPACITORS ARE IN pF
(A)
BASS
R2
BOOST I MEG ATTEN
R6
300N
(B)
POPULAR ELECTRONICS
V-
90
AmericanRadioHistory.Com
(2201 Laurelwood Road, Santa Clara, CA 95054). In each
circuit, resistors are rated for 1/4 or I/2 watt, while the
capacitors may be ceramic, mica, plastic or tubular paper
types, except where a dc polarity is shown, in which case
an electrolytic should be used. Capacitor working voltages
should be chosen on the basis of the do supply voltage
used, of course, with 50 -volt, or better, units adequate for
all four circuits. Although p -channel devices are indicated,
comparable n -channel FET's may be substituted in each
design if dc polarities are reversed and if bias and supply
voltages are readjusted for optimum performance.
Suitable for use as the first stage of a transmitter,, as a
marker generator, and in similar applications, the FET
crystal -controlled oscillator shown in Fig. 1A requires rela-
tively few components. The original design specified a type
2N2608 for Q1, a 1 -MHz crystal, and a 22 -volt dc power
supply. It may be assembled on a pert board, etched circuit
board, or even on a small chassis using point-to-point
wiring techniques.
In operation, the drain -gate feedback needed to start
and sustain oscillation is provided by stray interelectrode
and wiring capacities. Gate bias is established by source
resistor R2, shunted by bypass capacitor C2. Drain tuning
is provided by adjustable inductance L1, shunted by Cl.
The L and C values specified are for 1 -MHz operation but
these may be changed, of course, for other frequencies.
Featuring separate treble and bass controls, the tone -
control circuit illustrated in Fig. 1B may be used with virtu-
ally any audio amplifier-phonographs, tape recorders or
playbacks, or PA systems. Depending on application, it can
be assembled as a separate control or incorporated as part
of more complete amplifiers. Except for the treble control,
R4, standard components are used throughout the design.
As in the previous circuit, a 22 -volt dc power supply should
be used, and Q1 is specified as type 2N2843.
In operation, Q1 serves as a conventional common -
source amplifier, with gate bias provided by source resis-
tor R8, bypassed by C5. Resistor R7 serves as the drain
load and C1 and C6 as the input and output coupling
capacitors, respectively. A variable frequency response
characteristic is achieved by a combination of attenuation
and negative feedback techniques. When bass control R2
is shifted toward its BOOST position, it serves as a shunt
across C2, increasing the amplitude of the bass portion of
the applied signal. When R2 is set toward its ATTEN posi-
tion, its shunting effect across C2 is reduced and, at the
same time, a negative feedback signal coupled back from
the drain through R6 serves to reduce effective stage gain
at the lower frequencies. A similar technique is used for the
treble control. With treble control R4 in its maximum boost
position, C4 serves as a high -frequency shunt across the
bass control network. With R4 set forr maximum attenua-
tion, high -frequency negative feedback from Q1 's drain is
applied through C4 to the gate electrode, effectively reduc-
ing stage gain.
You can use the phase shifter circuit shown in Fig. 2A in
test instruments, such as oscilloscopes, in demonstration
projects, and in musical synthesizers. It requires a 12 -volt
dc supply when 2N2609 FET's are used for Q1 and Q2.
In operation, Q1 and Q2 are used as cascaded split -load
amplifiers, with R3 and R6 serving as the drain loads and
R2 and R7 as the source loads, respectively. Networks
C1 -R4 and C2 -R5 provide a control over the signal phase
shifts, with each stage supplying a controllable shift from
0° to 180°.
IN
IN
R3
2.2K
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4.7K
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R4 R5
250K n 250
R2
2.2K
(A)
Fig. 2. Phase shifter (A) and
automatic gain control (B).
v+
OUT
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ELECTRONICS Never i.
4>- R.IM i1°<W f
' eeryi'
In t6ü
,.I,o.y The 1975
L
Engineering
, `'. ' Manual &
T '-:
19151505I9IXL MAYIAI f 012_915195 GUIDE X, 50
Purchasing
Guide!
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Fort Worth, Texas 76102
NAME
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(-1)
l?
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. 6
e- ADDRESS I >
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CITY
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STATE MP T
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A DIVISION OF TANDY CORPORATION -
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NOVEMBER 1974 91
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IF YOU ARE READY FOR SERIOUS CAREER
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program arrangements with fourteen areas of
specialization in advanced electronics. You
can select exactly the area of specialization
for the career you want.
CREI also offers program arrangements
both for those with extensive experience in
electronics and for those with only limited
experience. All programs are college -level,
except for a brief introductory level course,
which is optional.
Unique Laboratory Program. CREI now offers
a unique Electronic Design Laboratory Program
to train you in the actual design of electronic
circuits. You also get extensive experience in
tests and measurements, breadboarding, pro-
totype building and in other areas important
to your career. The Lab Program makes it
easier for you to understand the principles of
advanced electronics. Only CREI offers this
complete college type laboratory program.
The Lab Program includes professional
equipment which becomes yours to keep.
You will especially appreciate the Electronic
Circuit Designer, which is available only
through this program and which you will find
extremely valuable throughout your profes-
sional career.
College Credit. You can actually earn college
credit through CREI programs, which you can
use at recognized colleges for an engineering
degree. CREI maintains specific credit transfer
arrangements with selected colleges in the U. S.
Industry Recognized Training. For nearly
50 years CREI programs have been recognized
throughout the field of electronics. CREI
students and graduates hold responsible
positions in every area of electronics and are
employed by more than 1,700 leading organi-
zations in industry and government.
Qualifications to Enroll. To qualify for enroll-
ment, you should be employed in electronics
or have previous experience or practical train-
ing in the use of electronic equipment. You
must also be a high school graduate or true
equivalent.
All CREI Programs are available
under the G.I. Bill
Send for FREE Book. If you are qualified,
send for CREI's full color catalog describing
these college -level programs and your career
opportunities in advanced electronics. Mail
card or write for your copy of this book.
CAPITOL
RADIO
ENGINEERING
H'I INSTITUTE
McGraw-Hill Continuing Education Center
3939 Wisconsin Avenue Northwest
Washington, D. C. 20016
Accredited Merrtber, National Home Study Council
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FOUR CHANNEL DIGITAL
HANDHELD MEMORY SCOPE
MS -416 is a valuable tool for circuit analysis:
TV. - stereo receivers - electronic calcula-
tors - digital clocks - digital auto electronics
and,more. The MITS MS416- digital pocket
scope Is a four -channel, digital logic
oriented, handheld scope with full mem-
ory capability. The clock time -base
is from .5 sec. to 200 m sec. The
scope may be operated in two modes, selected SIZE: 53//44" e..'v." x 11/2"
by another switch. Besides the normal mode, there is a store mode which
enables the scope to remember the information on all four channels within
the time -base range and display it continuously.
SPECIAL OFFER
MS -416 regular price $189.50
order now for $161.50
Prices, specifications and delivery/su6lect to
change without notice. WARRANTY: 1 year
,416
mits®cr*
[re Iectronics"
Enclosed is a Check for $
or BankAmericard #
or Master Charge #
Credit Card Expiration Date
Include $5.00 for Postage and Handling
MS -416
Please send information on Entire MITS Line.
NAME
ADDRESS
CITY
STATE & ZIP
MITS / 6328 Linn, N.E., Albuquerque, New Mexico 87108 505/2651553 Telex #660401
L CIRCLE NO. 27 ON READERS SERVICE CARD
~
GREEÑ LE@
I"
Put more
punch in your work.
With a Greenlee Chassis Punch you can punch
clean, true holes in seconds. Round, square,
key or D. In 16-ga. metal, hard rubber, plastic
or epoxy. Available at radio and electronics
parts dealers. Write for catalog E-730.
Greenlee Tool Co, Rockford, Ill. 61101.
GREENLEE TOOL CO
Ex -Cell -0
Corporation
There are probably many uses you can devise for the
audio automatic gain control (agc) circuit illustrated in Fig.
2B. Use it to maintain a constant level in a tape recorder, to
prevent overmodulation in a transmitter, or as part of an
expander or compressor. According to Siliconix, the cir-
cuit will provide an effective agc range of 60 dB and has a
frequency response flat to within 1 dB from 1.0 Hz to better
than 10 kHz. Type U112 devices are specified for both Q1
and Q2, with a 12 -volt dc power supply.
In operation, Q1 serves as a variable resistance, Q2 both
as a gate bias control for Q1 and as a source -follower
amplifier. Series resistor R1 and Q1's source -drain resis-
tance, shunted by R2, form a simple voltage divider. FET
Ql's source -drain resistance, in turn, is determined by its
gate bias, which is established by Q2's drain current and
the agc voltage applied to Q2's gate. As increasing agc
voltage is applied, Q2's drain current is reduced, increas-
ing Q1 's negative gate bias and thus reducing Q1 's effec-
tive source -drain resistance, thus reducing the effective
level of the input signal applied through C2 to Q2's gate
and, therefore, the output signal developed across Q2's
source load, R4. As the agc voltage is reduced, the oppo-
site action takes place, increasing the output signal level.
Although the parameters of the agc circuit are not criti-
cal, one simple adjustment is required for optimum per-
formance. Wirth the circuit wiring completed and checked,
apply the dc supply voltage, a small input signal, and zero
agc voltage. Adjust drain load R5 for a maximum output
signal across source load R4.
If you've been intrigued by our discussion of the versatile
FET and would like to explore the subject in greater detail,
we can recommend any (or all) of the following books:
An Introduction fo Field Effect Transistors, by J. Watson,
published by Siliconix, Inc.
FET Circuits and abc's of FET's, both by Rufus P. Turner,
published by Howard W. Sams & Co., Inc.
Field Effect Transistor Projects, published by Motorola,
Inc., Semiconductor Products Division, and offered
through HEP distributors.
Reader's Circuit. Featuring a popular IC op amp and a
pair of zener diodes, the portable scope calibrator circuit
given in Fig. 3 was submitted by reader Ted Reiter (1442
Brook Drive, Titusville, FL 32780). Layout and lead dress
are not critical and the project can be duplicated quite
easily in a single evening or on a weekend by the average
hobbyist.
In this circuit, IC1 serves as a simple relaxation oscil-
lator, supplying an output signal which is clipped by zener
diodes D1 and D2 in conjunction with series resistor R4,
Fig. 3. Reader's circuit for
portable scope calibrator.
R0
270 K
I ` F
R4
1.8K
OUT
CIRCLE NO. 19 ON READERS SERVICE CARD
96 POPULAR ELECTRONICS
AmericanRadioHistory.Com
troñics catal
197 5 elec
. Laf a E1 ,ic5
Listen to us.YougoMronB
.
no: 15 5 - I,
The "NEW LOOK"
1975
LAFAYE E
RADIO ELECTRONICS
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Y NATIONALLY p MAJOR
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f MAIL TODAY!
If jot.'re interested in electronics you NEED
this catalog! Completely re -designed for easier -
than -aver odering, with the newest and best
Lafayette and national -brand products tor '75.
And you gel the same quality and service
:hat has made Lafayette a leader or 55
seats. Iror-clad guarantees! Lowest Prices!
Pro'essionat Service! State-of-the-art Equip-
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than ever, we' -e your "Single -trip" shop-
pu1g center for everything in electronics.
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ers Car Stereo and Accessories
Antennas Cameras TV FA and
Test EgLipment Music InstrLments
and Amplifiers Books Electronic
Calculators Secuity Systems
PLUS PARTS, TUBES, BATTERIES,
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FOR QUALITY LIV NG THROUGH
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a ette
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STORES COAST TO COAST Check Your Yellow Pages or Shcp by Mall
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AmericanRadioHistory.Com
developing a fixed -level square -wave
output signal with a peak -to -peak am-
plitude equal to the total zener vol-
tage. Operating power is supplied by
batteries 81 and B2 controlled by a
dpst switch, S1.
Readily available standard compo-
nents are used in the design. Ted
chose a type 741 op amp for ICI. The
terminal numbers shown are for the
"minidip" version used in his original
model. The resistors may be either 1/4
or 1/2 watt, while Cl is a low -voltage
ATTENTION
HOBBYISTS!
BUILD THIS
DIGITAL
COUNTER/ L.E.D.
DISPLAY --
KIT. 5017-;_1-7-..,
Everything needed to build a complete decade
counter (0-9) including a printed circuit board.
Operates from a 5 Volt D.C. supply. Can be
used in hundreds of applications.
See your nearby CALECTRO
distributor for all the most
popular digital displays and
integrated circuits. Also, get
your copy of the new
CALECTRO DIGITAL
PROJECTS HANDBOOK!
GC
ELECTRONICS: GC ELECTRONICS
} ; Division of Hydrometals, Inc.
Rockford, Illinois 61101 U.S.A N d
98
ceramic capacitor. Batteries 81 and
82 are conventional 9 -volt transistor
units, with S1 a toggle, slide or rotary
switch. Ideally, the zener diodes
should be matched, with a total vol-
tage of 10 volts. Unable to obtain a
perfect match, Ted assembled his
model using a 5.6 -volt zener for D1, a
4.5 volt device for D2, providing a
nominal 10.1 -volt output signal. The
actual output voltage, of course, will
depend on the zener diode voltage
tolerances.
If a particular application requires
an accurately known output voltage, a
simple test will establish this value.
Disconnect R4's upper lead (pin 6,
ICI). Reverse D2. Connect R4's free
lead to the positive terminal of a
15 -18 -volt dc source, negative to cir-
cuit ground. Finally, measure the dc
voltage across the series zeners using
an accurate voltmeter. Restore the
circuit to its original condition for
normal operation.
Device/Product News. We've re-
ceived a number of inquiries from
readers asking what LED's have the
lowest current ratings. Actually, most
LED's will operate at currents much
lower than their maximum ratings,
and we've obtained satisfactory light
outputs with levels as low as 8 to 10
mA using commercial 50-mA (max)
devices. However, the results are not
consistent. One LED of a given type
may provide a good output at a 7-mA
level, while another of the same type
may require 10 mA, and still another 12
or 15 mA. At least one firm, however,
Data Display Products (5428 W. 104th
St., Los Angeles, CA 90045), offers
complete LED panel -light assemblies
designed to be used at a mere 5-mA
current level. Available colors are
green, yellow, amber and red, at vol-
tages from 1.8 to 28 V. Single unit
prices range from $1.58 for a 1.8 -volt
device (requiring an external current
limiting resistor) to $1.76 for a 28 -volt
type (with built-in resistor). Each unit
is supplied with a mounting clip and
Neoprene washer.
You can add another name to the
roster of firms manufacturing dual
555 -type timer IC's: Silicon General,
Inc. (2712 McGaw Ave., Irvine, CA
92705). Packaged in 14 -pin DIPs, the
Silicon General version is identified as
the SG556/SG556C.
Perhaps a dual timer is not enough
for your application. If this is the case,
you might check the new quad timers
now available from Signetics (811 E.
Argues Ave., Sunnyvale, CA 94048).
Identified as Models 553 and 554, the
new units are supplied in a 16 -pin DIP.
The 553 and 554 are not exact dupli-
cates of the industry standard, the
familiar 555, however. They have no
reset control line and a common con-
trol voltage pin is provided for all four
timers in the package. Basically simi-
lar in application, the 553 is rated to
sink 100 mA, the 554 to source an
equivalent current, compared to the
200 mA ratings of the 555/556 types.
Another interesting difference be-
tween the 553/554 devices and the
555/556 types is a simplification of
their timing equations, from T = 1.1 RC
to T = RC for the new units.
How many watts in a dollar? If this
seems like a silly question, compara-
ble to a mixing of apples and oranges,
it is, however, the type of question that
a transmitter designer must ask him-
self. According to Motorola, its new
MRF621 uhf power transistor can de-
liver an output signal in the 406 -to -
512 -MHz band for less than a dollar
per watt. Designed for 12.5-V dc opera-
tion, the new device can deliver 45 W
at 470 MHz with a minimum power
gain of 4.8 dB and collector efficien-
cy of 55%. Featuring an internal MOS
capacitor chip for "controlled -Q"
operation, the MRF621 sells for
$39.00 each in unit quantities, even
less if you want to buy 25 or more at
a time.
RCA's Solid State Division (Box
3200, Somerville, N.J. 08876) has in-
troduced a new linear IC and added
another COS/MOS device to its ex-
panding line. Designated type
CA3127E, the new linear device con-
sists of 5 independent general-
purpose silicon npn transistors con-
structed on a common monolithic
substrate to provide close electrical
and thermal matching. Suitable for
low -power applications at frequencies
up to 500 MHz, the CA3127E, supplied
in a 16 -lead plastic DIP, can be used in
vhf amplifiers, mixers and oscillators,
in i -f converters and amplifiers, and in
sense amplifiers, synthesizers, and
cascade amplifiers. RCA's latest
COS/MOS device, identified as the
CD4093AE, is a quad 2 -input NAND
gate consisting of four identical
Schmitt trigger circuits, each of which
functions as a two -input NAND gate.
The CD4093AE, packaged in a 14 -pin
plastic DIP, is suitable for use in
wave -shapers and pulse -shapers, mon-
ostable and astable multivibrators,
and NAND functional logic circuits.*
POPULAR ELECTRONICS
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FREE! bargain catalog. Fiber optics. LED's. transistors,
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WE SELL CONSTRUCTION PLANS. TELEPHONE:
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Phonevision, Auto Dialer, Touch Button Dialer, Central
Dial System. TELEVISION: $35.00 Color Converter, Video
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Microscope, 96 Hour Tape Music System, Ultrasonic Dish-
washer, Radar -Oven. Plans 54.95 each. NEW ITEM: $75.
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IC Producing Sine. Square, Triangular Waveforms, $10.95
PPD. 8038 IC. $6.75 each PPD. PHOTOLUME
CORPORATION, 116 East 28th Street. New York, NY 10016.
LOOKING FOR A NEW CHALLENGE?
.. than bulk/ a TV cameral
vior-- ONLY SOLID STATE CAMERA AVAILABLE IN KIT FORM
OR FACTORY ASSEMBLED. COMPLETE KIT WITH V101.
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DIGITAL ELECTRONICS: Complete schematics. parts
lists, theories - Discrete Component Digital Clock,
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MECHANICAL, ELECTRONIC devices catalog 10 cents.
Greatest Values - Lowest Prices. Fertik's, 5249 "D",
Philadelphia, Pa. 19120.
SOUND SYNTHESIZER KITS -Surf $12.95, Wind $12.95,
Wind Chimes $17.95, Electronic Songbird $6.95, Musical
Accessories, many more. Catalog free. PAIA Electronics,
Box J14359, Oklahoma City, OK 73114.
FREE CATALOG. Parts, circuit boards for POPULAR
ELECTRONICS projects. PAIA Electronics, Box C14359,
Oklahoma City, OK 73114.
COMPLETE CONSTRUCTION PLANS- TELEPHONE: An-
swering Device, Automatic Dfaler. "Black Boxes", Call
Diverter. Call Limiter, Conference Bridge. Central Dial
Exchange. Melodic Ringing, Recorder -Actuator, Remote
Control. Schematics, Speakerphone, Telelink Burglar
Alarm, Voice Scrambler. 53.00 each. ELECTRONIC:
Biofeedback Conditioner, Horticulture Stimulator.
Mu Itilrequency Encoder Network (Speeds telephone
calling 100%!). 55.00 each. DODECAHEDRON Speaker
Enclosure 57.50. Photographic Pinhole Camera $2.00. ONE
YEAR SUBSCRIPTION: Telephone -Electronics Newsline
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BURGLAR -FIRE alarm supplies and information. Free
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Michigan 48415.
t""
-= Ij
HAS...
® modular
SYNTHESIZER
KITS
demo
record 5100
free catalog
PAIA ELECTRONICB, INC.
BOX P14359, OKL.AMOMACFTV,OK-73114 r
AUTHENTIC. INSTRUMENTED, FLYING ROCKETS for
casual or serious experimenters. Over 80 scale original.
multi -stage or ready -to -fly models. Solid -propellant
engines for safe, electric launch system liftoffs up to 2.500
feet. Measure altitude, temp. inversions, more. Real
telemetry, electronic tracking, aerial still and movie photo-
graphy with super -miniaturized equipment. New, detailed
tech manual and full -color catalog. 25 cents from ESTES
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ELECTRONIC Parts wholesale. Catalog 10 cents. Donlyn
Electronics, P.O. Box 15421, Phoenix, Arizona 85060.
INTERNATIONAL ELECTRONICS UNLIMITED
TTL
7400 S .19 7474 S .43
7401 .19 7475 .75
7402 .19 7476 .47
7403 .19 7483 1.11
7404 .22 7486 .44
7405 .22 7489 2.75
7406 .39 7490 .76
7407 .39 7491 1.29
7408 .25 7492 .79
7409 .25 7493 .79
7410 .19 7494 .89
7413 .79 7495 .89
7415 .39 7496 .89
7416 .39 74107 .49
7417 .39 74121 .57
7420 .19 74123 .99
7423 .35 74125 .69
7425 .39 74126 .79
7426 .29 74141 1.23
7427 .35 74145 1.15
7430 .22 74150 1.09
7432 .29 74151 .89
°B 7437 .45 74153 1.29
7438 .39 74154 1.59
7440 .19 74157 1,29
7441 1.09 74161 1.39
7442 .99 74163 1.59
`F 7443 .99 74164 1.89
7444 1.10 74165 1.89
7445 1.10 74166 1.65
7446 1.15 74173 1.65
7447 1.15 74177 .99
7448 1.15 74180 1.09
7450 .24 74181 3.65
7453 .27 74182 .89
7454 .39 74190 1.59
7460 .19 74193 1.39
7464 .39 74194 1.39
7465 .39 74195 .99
7472 .36 74198 2.19
7473 .43 74199 2.19
DATA SUPPLIED ON REQUEST
WITH ORDER. ADD 8.50 PER DATA
FOR ITEMS PRICED UNDER S1,00
I-
4000 SERIES RCA-EQUIV.
301
° 307
308
309K
311
319
324
339
LINEAR CIRCUITS
Hi pert. op amp mDIP
Op amp mDIP
Micro-pwr op amp mDIP
5V reg 1A TO -3
Hi perf. V comp 10DIP
Hi -speed dual comp DIP
Quad op amp DIP
Quad comp DIP
340T Pos V reg (5V, 6V, 8V,
12V, 15V, 18V, 24V) TO -220
380 2w audio amp DIP
380.8 .6w audio amp mDIP
381 Lo noise dual preamp DIP
550 Prec. V reg ' DIP
555 Timer mDIP
560 Phase locked loop DIP
565 Phase locked loop DIP
709 Op amp DIP
723 Volt reg. DIP
741 Comp. op amp mDIP
747 Dual 741 DIP
748 Freq adi 741 reDIP
1458 Dual Comp op amp mDIP
8, 3900 Quad amp DIP
3905 Prec. timer DIP
8038 Function gen. DIP
75451 Dual prl. driver reDIP
75452 Dual prl. driver rnDIP
75453 Dual prl. driver mDIP
75491 Quad seq driver DIP
75492 Hex dig. driver DIP
DATA SUPPLIED ON REQUEST
WITH ORDER. ADD S.50 PER DATA
FOR ITEMS PRICED UNDER $1.00
LOGIC PROBE KIT
S .32 Ten nano/sec capability
.35 Checks TTL & DTL logic
1'10 Dual slope memory
1.65 Internal 5V regulator
1.05 Kit is complete with all necessary compo-
t1'96 next. case, probe, complete instructions
and logic chart $19,95
1.69
1.95
1.49
.89
1.79
.79 .99
2.75
2.65
.29
.69
.35
.79
.39
.69
.65
.65
5.95
.39
.39
.39
.79
.89
CALCULATOR & CLOCK CHIPS w/data
5001 LSI 40 pin DIP 4 funct S 3.95
5002 LSI Same as 5001 exc batt pwr 8.95
5005 LSI 28 pin DIP 4 functw/mem 8.45
MM 5311 28 pin BCD 6 dig raux 9.95
MM 5312 24 pin 1 pps BCD 4 dig mux 6.95
MM 5313 28 pin 1 pps BCD 6 dig mux 7.95
MM 5314 24 pin 6 dig mux 8.95
MM 5316 40 pin alarm 6 dig 12.95
POWER SUPPLY SPLITTER KIT
Ground reference for positive & negative -
output from single supply - any DC
source to 20V
Balanced output adjustment
1 amp -current capability with sink
e
Increase usefulness of your power supply '
Complete with all components &
instructions S4 95
1101
1103
5260
7489
8223
MEMORIES
256 bit RAM MOS
1024 bit RAM MOS
1024 bit RAM low power
64 bit RAM TTL
Programmable ROM
51.75
4.95
3.95
2.75
4,95
I -
° LED'S AND OPTO ISOLATORS
MV10B Red TO 18 S .25 ea.
MV50 Axial leads .20
MV5020 Jumbo visible red .33
ME4 Infra red diH. dome .60
" MAN1 Red 7 seg..270" 2.50
MAN2 Red alpha nulo .32" 4.95
MANSA Red 7 seg..127" .79
MAN3M Red 7 seg..127" claw 1.15
MAN4 Red 7 set..190" 2.15
MANS Green 7 seg..270" 2.95
MAN7 Red 7 seg..270" 1.35
MANS Yellow 7 seg..270" 3.95
MAN66 60" high dir. view 4.65
DL707 Red 7 seg..3" 2.15
MCD2 Opto-iso diodes 1.09
MCT2 Opto'iso transistor .69
ON ORDERS OVER $25.00 DEDUCT 10%
All items are new, unused surplus parts - tested functional.
Sadsfaction is guaranteed. Shipment will be made via first class
mail - postage (paid - in U.S., Canada and Mexico within three
days from receipt of order. Minimum order - $5.00. California
residents add sales tax.
INTERNATIONAL ELECTRONICS UNLIMITED
P.O. BOX 1708 MONTEREY, CALIF. 93940 USA
I
CIRCLE NO. 21 ON READERS SERVICE CARD
NOVEMBER 1974 99
CD4001 S .55 CD4017 2.95
CD4009 .85 CD4019 1.35
CD4010 .85 CD4022 2.75
CD4011 .55 CD4023 .55
CD4012 .55 CD4025 .55
CD4013 1.20 CD4027 1.35
CD4016 1.25 CD4035 2.85
14081.659-4773
AmericanRadioHistory.Com
DIP SOLDER TAIL SOCKETS
DUAL IN-LINE SOLDERCONTA TAIL SOCKETS
TS
8 PIN ....44 18 PIN . .74 28 PIN ... 1.30
14 PIN .. ..52 22 PIN . . . 1.00 36 PIN . . . 1.55
16 PIN ....54 24 PIN . . 1.05 40 PIN . . . 1.75
Also available - wire wrap sockets - 1/2/3 levels write or call for
large volumn DISCOUNTS
TTL
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7413
7416
7417
7418
7420
7421
7423
7425
7426
7427
7429
7430
7432
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7450
7451
S .18
.23
.23
.23
.25
.24
.50
.50
.25
.25
.23
.30
.89
.45
.45
.25
.23
.27
.32
.27
.31
.32
.40
.33
.26
.45
.50
.50
.23
1.10
1.05
1.10
1.15
1.10
1.25
1.25
1.25
.25
.27
7453 $ .27
7454 .40
7459 .25
7460 .25
7470 .45
7472 .41
7473 .47
7474 ,47
7475 .90
7476 .47
7480 .50
7482 1.75
7483 1.15
7485 1.10
7486 .47
7488 4.00
7489 3.00
7490 .89
7491 1.15
7492 ,95
7493 .95
7494 .97
7495 .95
7496 .95
74100 1.50
74107 .47
74121 .55
74122 ,47
74123 1.05
74125 .60
74126 .80
74141 1.15
74145 1.15
74150 .95
74151 L20
74153 1.50
74154 1.25
74155 1.30
74156 1.30
74157 $1.55
74160 1.65
74161 1.65
74163 2.50
74164 2.50
74165 2.50
74166 1.75
74170 3.00
74173 1.75
74174 1.85
74175 1.85
74176 .85
74177 .85
74180 1.05
74181 3.75
74182 1.00
74184 2.30
74185 2.30
74187 7.00
74190 1.50
74191 1.50
74192 1.50
74193 1.50
74194 1.50
74195 1.05
74196 1.25
74197 1.05
74198 2.25
74199 2.75
74200 7.00
PROJECTS
8263 Sig. 7.00
8267 4.00
2513 14.00
2518 7.00
2424 7.00
2425 7.00
4024 2.25
CMOS
C 04001
CD4002
CD4009
CO4010
CD4011
CD4012
CD4013
CD4016
CD4023
CO4025
CD4027
CD4030
74C00
74C04
74C20
74C173
S .55
.55
1,40
.60
.55
.55
1.50
1.40
.55
.55
1.25
.60
.45
.70
.65
2.60
8000 Series
8090 $ .35
8091-8098 .55
8223 5.00
8280 .75
8288 1.15
8880 1.35
Many Other
8000 Series
LEDS
MV 10
MV 50
MV 5024
MAN -1
MAN.3
MAN -4
MAN -7
DL 33
5/1
6/1
5/1
1.95
.95
1.95
1.50
1.95
20% Discount for 160 Pieces Combined - Above 7400 Series
041.9 E%$PECIAL$ øot
1144148 Silicon Signal Switching Diode 15/1.00
TIS37 - TiS98 NP!J Transistor 10/1.00
7400 - 7401 - 7403 GATES 6/1.00
7404 - 7410 - 7420 GATES 5/1.00
LM301H/LM301N OP. AMP. 3/1.00
LM309K 5 V 1 AMP 1.25
LM311N/LM311N Comparators 1.00
LM380N 2 Watt Audio AMP 1.25
LM3900N Quad AMP DIP .55
LM3905N Precision Timer .65
LM741CH/LM741CN OP. AMP. 3/1.00
MM5314 24 Pin Digital Clock Chip 7.95
MM5316 40 Pin Alarm Clock Chip 11.95
MM5016H 512 Blt Dynamic Shift Reg. 2.00
MM1103 1024 X 1 Bit Dynamic RAM 3.95
2519 40 X 6 Static Shift Register 4.00
2529 240 X 2 Static Shift Register 5.00
LM300
LM 301 H/N
LM302H
LM304H
LM305H
LM307H/N
LM308H/N
LM309K
LM31oH
LM311H/N
LINEAR
Pos. V Reg To 5
Improved Op Amp
Voltage Follower
Negative Voltage Regulator
Positive Voltage Regulator
Op Amp (Super 741)
Micro Power Op Amp
5 Volt Regulator / Amp
Improved Volt. Follwer Op Amp
Hi -performance Volt. Comp.
LM319H Hi -Speed Dual Comp.
LM32OK-5V-15V - To 3 Neg. Regulator
LM324N Quad 741 Op Amp
LM339 Quad Comparator
LM340K-5V-12V-15V-24 Positive Volt Regulator
LM37ON A 6 C - Squelch Amp.
LM373N AM/FM S$B Strip
LM38ON 2 Watt Audio Power Amp
LM703H RF/IF Amp
LM5558V Dual Op Amp
$ .85 .40
.85
1.10
1.00
.40
1.15
1.70
1.35
1.15
1.55
1.75
1.90
2.35
2.00
1.55
3.30
1.50
.45
1.00
LM741 H/N Comp. Op Amp .40
LM747H/N Dual Compen. Op Amp .90
LM748N Freq. Adj. 741 .40
LM1458N Dual Comp. Op Amp .65
LM3065N T.V.-FM Sound System .75
LM3900N Quad Amp .65
LM555N Timer 1.00
LM565-LM566-LM567 Phase Looked Loops 2.50ea
LM 7522 Core Memory Sense Amp. 2.50
LM 7524 Core Memory Sense Amp. 1.50
LM 7535 Core Memory Sense Amp. 1.00
LM75451 Dual Peripheral Driver .49
LM75452 Dual Peripheral Driver .49
LM75453 Dual (LM3511 .65
Satisfaction Guaranteed. All Items 100% Tested
$5.00 Min. Order - 1st Class Mail - No Extra Charge
California Residents - Add 6% Sales Tax
Wholesale Outlets - Write for Special Discounts
Write for FREE Catalog - Data Sheets .20 i each
JAAJ
Electronics
P. 0. Box 822 -Belmont, Ca. 94002
PHONE ORDERS WELCOME
(4151 592-8097
CIRCLE NO. 22 ON READERS SERVICE CARD
100 POPULAR ELECTRONICS
WE SELL MONEY MAKING CONSTRUCTION
MANUALS! -Reclaim refined GOLD and SILVEP for
EXCELLENT full time or part time money! -Color Catalog
25 cents -Airmailed 50 cents. Creative Products, Dept PE -
1174, 8415 Lotland, Houston, Texas 77055.
BUGGED??? New locator finds them fast. Write, Clifton,
11500-L N.W. 7th Avenue, Miami, Florida 33168.
TELEPHONE "BUGGED"? Countermeasures Brochure
$1.00, Negeye, Drawer 547, Pennsboro, W. VA 26415.
HEAR POLICE/FIRE Dispatchers! Catalog shows exclusive
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cent stamp. Communications, Box 56 -PE, Commack, N.Y.
11725.
YOU WILL SAVE BIG MONEY! Surplus, Clearouts,
Bankruptcy, Inventory, Deals. Catalog $1 (redeemable).
ETCOA Electronics, Box 741, Montreal, H3C 2V2. U.S.
Inquiries.
CONVERT any television to sensitive. big -screen oscillo-
scope. Only minor changes required. No electronic
experience necessary. Illustrated plans. $2.00. Sanders,
Dept. A-33, Box 92102, Houston, Texas 77010.
CONSTRUCTION PLANS: Laser...52.00. Rocket Tracking
Transmitter...52.00. Space Monitor -Missile
Tracker... $2.00. Free Catalog. Electro -Research, P.O. Box
20285, Ferndale, Michigan 48220.
CD IGNITIONS, VHF/UHF monitors, crystals, CB radios,
Southland, Box 3591-B, Baytown, Texas 77520.
CRYSTALS, Scanners, $3.88, include make and frequency.
G Enterprises, P.O. Box 461PC, Clearfield, UT 84105.
PRACTICAL Applications of Digital IC's. 100's of tips,
circuits. projects. on TTL. 443pp $19.95. Money Back
Guarantee, GEA, P.O. Box 285, Northfield, Ohio 44067.
FREE CATALOG. Kits, Components, audio equipment.
Electronic Supply Pecs, Box 175, Floral Park N.Y. 11001.
ALPHA/THETA BRAINWAVE biofeedback instruments,
Analog instruments from $125; digital processing systems
from $225. BioScan, Box 14168-E, Houston, Texas 77021.
SURPRISE! Build inexpensively, the most Unusual Test
Instruments, Futuristic Gadgets using Numerical
Readouts! Catalogue Free! GBS, Box 100A, Green Bank,
West Virginia 24944.
ELECTRONIC ORGAN KITS, KEYBOARDS and many
components. Independent and divider tone generators. All
diode keying. I.C. circuitry. Supplement your Artisan
Organ, 35 cents for catalog. DEVTRONIX ORGAN
PRODUCTS, Dept. C., 5872 Amapola Dr., San Jose, Calif.
95129.
ELECTRONIC IGNITION: Capacitor, transistor, pointless.
Auburn sparkplugs. Information 10 cents. Anderson
Engineering, Epsom, N.H. 03234.
WHOLESALE Scanners. CB, Crystals, Directories,
SSB/AM, Catalog 25 cents. G -Enterprises, Box 461P,
Clearfield, Utah 84105.
ELECTROENCEPHALOPHONE: Brainwave monitor.
Professional biofeedback tntruments. J&J, 8102-E,
Bainbridge, WA 98110.
HOBBYISTS -For all your electronic parts requirements at
low prices, send for free flyer to: Dartek Electronics, Dept.
P, Box 2460, Dartmouth, Nova Scotia, Canada. U.S. In-
quiries.
CALCULATOR OWNERS: Use Your +-x- calculator to
compute square roots, trigonometric functions, logarithms,
and more! Quickly, Accurately, Easily! Send today tor the
First and Best Calculator Manual ... now in use through-
out the world ... still only $2.00 Postpaid with Uncon-
ditional Money -Back Guarantee! Mallmann Optics and
Electronics, Dept. 21A, 836 South 113, West Allis,
Wisconsin 53214.
FREE 1975 Electronics Catalog. McCord Electronics, Box
276-N, Sylvania, Ohio 43560.
BUBBLE ETCHER. Etches 6"x8" board in halt time. Acrylic
construction. Complete photo process instructions.
Requires inexpensive aquarium pump. $12.00. ETCHER,
Box 25066, Northgate Station, Seattle, WA 98125.
AUTORANGING DMM, deluxe VOM's, logic probes and
more. Lowest prices. Free catalog. Electro Industries. 4201
Irving Park, Chicago, Illinois 60641.
ARE YOU PREPARED? 10,000 cubic foot. pull ring ignited
emergency smoke grenades are now available! 3 for $7.50.
9 for $20.00. Postpaid. Pacific Aero Supply, Box 601,
Malibu, Calif. 90265.
DIGITAL/ANALOG PLANS for Home and Lab!!! Send for
free 16 -page ideas catalog featuring the
EXPERIMENTER'S COMPUTER SYSTEM, practical plans,
tutorials, etc. M.P. Publishing Co., Box 378-P. Belmont,
Massachusetts 02178.
PYROTEChNICAL chemicals, casings, tools. supplies,
fuse. Price List 50 cents. Westech, Logan, Utah 84321.
SJ
hL
e all -new
!CATIONS
th -, ome th
CLEAR
1975 COM 111,LI
HANDBO
Here ís everyttlhá
you want to krái
need to know
about Citizen
Amateur Radi,o,/
Shortwave Li$ti~riri
si
DON'T TURNEAA,/DIAL`n fact don't even buy
a dial or any, h(rig ele bin I you've checked
out the 197 / C mu tions Handbook.
Whatever y t ur to s cialty - whether
you're an olci''i h bl tSt (getting started -
this vital "hip o g e Will help you get
greater valuee dry to ,'e tOjnent out of every
minute you 'pen dth otl,(lequipment.
COMMUN
is sclfef/'r¡l
nation$y
75
S ANDBOOK
d \Io on sale
jenlb21, 1974.
YOU CAN RESERVE
YOUR COPY NOW
AT THE SPECIAL
PRE -PUBLICATION
PRICE OF ONLY
$1.00 POSTPAID.
Regular newsstand price is $1.25,
mail order $1.60.
So to make sure you come through
"Loud and Clear" in 1975...
RESERVE YOUR COPY NOW AND SAVE
WITH THIS SPECIAL PRE -PUBLICATION
OFFER AVAILABLE TO READERS OF
POPULAR ELECTRONICS MAGAZINE ONLY.
PRE -PUBLICATION
RESERVATION FORM
Communications Handbook PE -1174
Ziff -Davis Service Division
595 Broadway
New York, New York 10012
Enclosed is $1. Please reserve my copy of
the 1975 Communications Handbook at the
special pre -publication price to be mailed
to me on or before November 21, 1974.
VIDEO GAMES -attaches to your TV. Ping-Pong plans
$3.50. Information 25 cents. Duncan Electronics, 20650
Runnymede, Canoga Park, Calif. 91306.
Print Name
Address
City
State Zip
PAYMENT MUST BE ENCLOSED WITH ORDER
AmericanRadioHistory.Com
AM -FM -
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WITH
ú0o -wane
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AM -FM -
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Another external panel consists of provisions for ex-
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Lower inputs for connecting tape deck that will ploy
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phono power connection. RED. CREEN and CLEAR in-
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red indicator on front panel for STEREO indicator.
Nos separate input to plug into mike, guitar and other
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Has controls on front panel. PHONO-
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MAN -1
MAN -3
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Char.
.27 .12
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REFLECTIVE BAR TYPES
SLA-1
SLA-3
SLA-11
SLA-21-
.33
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MAN -
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AUDIO POWER AMPS Sr -1050: s0 29.95
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CLOCK CHIPS as Low as
ON A "DIP" $7.77
MM5311 6digit 28 -Pin $7.77
MM5312 4 -digit 24 -Pin '7.77
MM5313 6 -digit 28 -Pin 7.77
MM5314 6 -digit 24 -Pin 7.77
MM5316 4 -digit 40 -Pin, Alarm
MM5316-4 no alarm 4.95
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48 HR. SERVICE
BASIC KIT ff1 - includes c all -function Ilex Key
Keyboard, Cal Tech CT5002 case, chip, 9 -digit
Antes LED display with built -on individual magnitieis.
Plus sheets.
BASIC KIT f2 - same as Basic Ifl except rnlculatui
chip is National 8 -digit 5M6725.
BASIC KIT ff3 - same as Basic p1 except calculator
chip is National 6 -digit h1515736 and 75492.
12 DIGIT BASIC ff4 - Key parts include: CT5001
chip, 4-3 digit readouts, factory etched PC board, case,
carrying case. 2 -resistor networks, decimal switch.
Wild Rover Keyboard with ON -OFF switch diagrams.
Sale $24.95
12 DIGIT BASIC "MEMORY" KIT ff5 - Key parts
for 4 -memory calculator. Case with "slight touch key-
board", CT5006 memory chip, 6 MAN 3's, ON -OFF
switch, book, (extend key allows 12 digits), Pr
boards). $19.95
LM -300 POS V.R. (super 723) TO -5 , , $ .81
LM -301 Hi-perlormaace op amp (A) ... .39
LM -302 Voltage follower TO -5 81
óLM -304 Neg. volt. Reg. 70.5 . 1.15
LM -305 Pos. Voltage Reg. TO -5 95
LM -307 Super 741 op amp (A) 39
LM -308 Hi -Q let type op amp TO -5 .... 1 09
LM -309H 5V Volt -Regulator TO -5 1 05
LM -309K 5V Volt. -Reg. 1 Amp TO -3 . 1 65
LM -310 Voltage -Follower TO -5 1 25
LM -311 Hi -pert. Volt. Comp. (A) 1 09
LM -318 Prec. HI -Speed DIP 1 95
LM -319 HI -speed Dual Comp. DIP . 1 50
LM -320 MINUS 5. 12 or 24V V.R. 70.3 1 50
LM -322 Prec. Timer 1.75
LM -324 Quad (4.741s in DIP) 2.19
eLM -339 Quad Comparator. DIP 1.75
LM -340 Pas. V.R. T03 -1 -Amp 5, 6, 12.
15, 18. 24V ....2.95
Dual Peripheral Driver DIP .69
ACC Squelch op amp. TO -5 1.50
R -F, I.E. op e p 1 25
AM -FM SSB I.A!D, TO.5 3 50
AM -FM SS IVAD TO -5 3.50
Pos. V. Reg. .65
Dual 2 -watt audio amp 2 69
600mW LM -380, minl DIP 1.69
LM -350
CJ LM -370
LM -371
LM -373
LM -374
LM -376
LM -377
LM -380
LM -381
S
0 u o o o o C
LM -382 Low noise dual pea amp DIP
LM -703 RF-IF amp, TO -S
LM -703M RF-IF, op amp, mini DIP
LM -709 Operational amplifier (A)
LM -710 Differential amplifier (A)
LM -711 Dual Differential Amp (A)
LM -723 Voltage Regulator (A)
LM -725 Instrument Op Amp
LM -733 Differential Video 1
LM -741 Freq. Comp. 709 (A)
LM-741CV Mini DIP 741C
LM -747 Dual 741 (A) ...... .89
LM -748 Freq. adjustable 741C (A) . .. .41
LM -1303 Stereo ore amp DIP 91
LM -1304 FM Stereo Multiplexer 1.25
LM -1307 FM Multi. Stereo Dem, DIP .. .91
LM -1458 Dual 741'. mint DIPS, TO -5 . .63
LM -1496 Modulator, Demodulator .... 1.00
LM -3026 Differential Ni/te amp 1 50
LM -3900 Quad "current mind'. amp .95
LM -4250C Programable op amp 2 50
LM -75451 Dual peripheral driver 44
LM -75453 Dual peripheral driver ...... .44
LM 75491 Quad seg. driver, LED (DIP) ... 1.65
LM -75492 Hex digit driver, 250ma, DIP 1.85
Low noise dual pre amp DIP .. 1.69
.. 1.89 59
51
.36
.45
.36 69 69 75 41 41
10 -Amp Power
Tab Plastic Unit
BUY ANY 100 -TAKE 25%
SCRS! TRIACS! PRV Sale
QUADRACS! res, Jr):
200
300
400
500
600
$ .75
.95
1.25
1.50
1.98
2.25
2.50
LINEAR
FACTORY pTAmserAeteRT MARR[p
531 HI slew rate op -amp (TO.S)....$2.50
O 532 Micro power 741 (TO.S) 2 50
533 Micro power 709 (TO -5) ' 2 50
536 FET Input op amp (TO -5) 2 95
555 Timer 2 u Seconds to 1 -hr. (A) ..1.25
556 5 Times faster than 741C 2.10
558 Dual 741 (DIP) 1 00
560 Phase lock loops (DIP) 2 95
561 Phase lock loops (DIP) 2 95
0 562 Phase lock loops (DIP) 2.95
565 Phase lock loops (A) . 2.95
566 Function generator (TO -5) 2 a5
3 567 Tone decoder (A) 2 95
702C Hi -grain, DC amp (TO -5) .49
704 TV sound IF system 1 50
O 711C Dual dlff, comp (A) .33
723C Voltage regulator (A) .69
741CV Freq. comp 709 (Miel DIP) .44.
748C Freq. adi. 741C (A) 44
753 Gain Block 1.75
739.739 Dual stereo preamp 1.98
741-741 Dual 741C (TO -5) .89
U ULN2300M Op amp with SCR 1 00
CA3065 Video Audio system 1.00
RC4195 Dual 15V Tracking V.R. 2.50
4136 Quad 741's (DIP) 2.50
RC.2556 Dual 555'. 2.25
O TVR-2000 Super 723, TO.5 1.00
BRAND NEW LOWEST PRICES (A) TO -5 or DIP '
BUY ANY 10 -TAKE 15% .
RUY ANY 100 - TAKE 25%
35 WATT AUDIO $3.98
AMPLIFIER BASIC 2 for §7
For Class AB use. Basic includes: Slgnetlr
540 30 transistor high power driver TO -5
IC", with a pair of complimentary 35- o
watt plastic transistors, i.e. 2N5296 non
and 256109 pop. With schematics, printed
circuit and parts board layouts.
LOWEST PRICES ON
NATIONAL
"CALCULATOR
CHIPS"
CT5001 12 -Digits, 40 Pin .. . $5.95 3 for $17.
CT5002 9 -Volt r vas' n of 5001 7.77 3 for $21.
CT5005 12 -Digits 28 -Pin .... 9.99 3 for $27.
with 3 -function memory.
MM5725 8 -Digits, 4-Funes. LED 4.95 3 for $12.
MM5736 6 -Digits, 28 -Pin, 9V 4.9S 3 for $12.
Inflation -Fi hting
ECONOMY I PRICES
Type Sala Order bv type number! SI er shretA nn renuext "ONLI" Factory Marked
0 SN7400 $.19 5N7430 .24 0 SN7472 .42 0 51474107 .49 0 514741617
5147401 49 0 5117432 _28 0 597473 .52 13 5974108 .95 5N74163
3 5147402 .24 SN7437 .45 SN7474 .39 0 SN74112 .95 0 5N74164
] 597403 .19 0 SN7438 .49 0 5147475 .91 0 SN74113 .95 0 51174165
0 5147404 .27 0 597440 .19 0 5147476 .52 0 SN74114 .95 0 51474166
0 5147405 .24 0 5147441 1.00 0 597478 .79 51174121 .49 0 5974173
0 SN7406 .79 0 5147442 1.00 0 597450 .59 0 51474122 .55 0 51474174
0 5147407 .48 0 597443 1.00 3 59741111 1.25 0 5974123 1.09 0 51474175
0 5147408 .27 0 5147444 1.00 S9741112 .99 0 5974125 .65 0 5974176
0 557409 .27 0 SN7445 1.00 3 5)47483 1.19 0 51474126 .89 0 5974177
0 5147410 ;19 0 5147446 1.10 0 597465 2.50 0 51474139 1.25 0 SN74180
0 5147411 .31 0 5147447 1.10 0 597488 .49 0 5974140 2.50 0 SN74181
0 SN7412 .55 0 597446 1.45 0 5117489 2.95 0 51174141 1.19 0 51474182
0 5147413 .89 S147450 .27 3 597490 1.81 0 5974145 1.19
0 5147414 2.25 5147451 .28 0 5117491 1.35 0 SN74148 2.95
0 5N7415 .45 SN7453 .28 0 5147492 .99 0 51474150 1.19
0 5N7418 .45 SN7454 .39 0 SN7493 .99 0 51174151 .99
0 597417 .50 SN7455 .28 0 5147494 1.05 0 5/174153 1.39
0 597420 .22 5117460 .26 0 SN7495 .99 0 51474154 1.69
0 5147421 .50 597461 .26 0 5147406 .99 0 51.474155 1.29
0 SN7422 .29 5147462 .39 0 51474300 1.55 0 5974156 1.45
0 SN7423 .32 SN7464 .39 0 51474104 1.25 0 5974157 1.45
0 5147425 .35 5117465 .39 El5974105 .95 0 51474158 1.45
0 5N7426 .31 5147470 .49 0 5974106 .95 0 5974160 1.85
5147427 .3S SN7471 .55
NEW!
NATIONAL
LM -340T VR's
TO -220 Case 1 Ame
a POSITIVE VOLTAGE
Type Volts -
LM -340-051 5 y Your Cho
CI LM-340-0676 v Ice
LM -340-081 e v $1.75 each
LM -340-127 12 v
LM -340 -1ST IS v
LM -340-18 T 18 v
LM -340.24 T 24 v Buy Any 3
Take 10%
1.59
1.75
2.85
2.85
1.85
1.85
2.25
1.99
1.25
1.25
1.10
3.95
1.05
51174185 2.34
51174187 2.34
51474192 1.59
5974193 1.59
5974194 1.89
SN74195 1.10
51174196 1.20
51174197 1.10
51174198 2.45
51474199 2.45
51474200 7.50
INTEGRATED CIRCUIT
SOCKETS
14.Pin, DIP ....S.45
I4 -Pin. Side Mount 1.06
016 -Pin, DIP ..... .50
TO -5, 8 or 10.Plns. .29
buy Any 3 0 a -Pin. (Mlnl DIP). .39
Take 109, 14 -Pin, Wire Wrap ...69c
Discount! 16 -Pin, Wire Wrap ...89c
Terms: add postage Rated: net 311
Phone Orders: Wakefield. Klass. (6171 215-3824
Retail: I6 -I8 Del Carmine St., Wakefield, hl ass.
(off Mater Street) C.O.D.'S 51A3' IIE !'IIONEII
20c CATALOG on Fiber Optics, 'ICs', Semi's, Parts
MINIMUM ORDER - $4.00
POLY PAKS
P.O. BOX 942E LYNNFIELD,MASS. 01940
- . . "-'mer"w-
NOVEMBER 1974 CIRCLE NO. 31 ON READERS SERVICE CARD 101
AmericanRadioHistory.Com
BURGLAR -FIRE ALARM components, hardware. Free
Catalog -Information. Silmar, 133 S. W. 57 Ave., Miami,
Florida 33144.
MULTI -PURPOSE OSCILLATOR: 200-5000 HZ., Parts
below $8, Thousand uses, Plans $2. TECHNICAL
BOOKLET "Oscillators", $2.50. IC POWER SUPPLY, Plan
$1.90. Littleton Hobby Circuits, P. 0. Box 453. Littleton,
Mass. 01460.
FREE KIRLIAN image on 35mm slide and details on Kirlian
equipment. Systecon, Department 30, Box 417, West
Hyattsville, Maryland 20782. (301) 596-5654.
NEW COLOR TELEPHONES, booklets about connecting
telephones, and telephone accessories. Details 25 cents.
Telephones, Box 29002-C, Queens Village, NY 11429.
SPEAKER enclosure 10 x 15 x 6, walnut finish, $4.00 each
ppd. Complete case listing 50 cents. DlgtTel, Box 6585,
Toledo, Ohio 43612.
CITIZEN'S radio. Free discount catalog. Capitol Sound,
Box 3523. Des Moines, lowa 50322.
CARBON FILM RESISTORS. Brand new as low as 2-1/4
cents. FREE samples and specifications. COMPONENTS
CENTER -PE, Box 134, New York, NY 10038.
7,000 SEMICONDUCTORS, 100's Electronic Circuit Kits.
Technical Reports, Energy Conservation, Computers. Cat.
50 cents. E/S Lab, Box 738, College Park, MD 20740.
UNSCRAMBLERS: Fits any scanner or monitor, easily
adjusts to all scrambled frequencies. Only 4" square
$29.95, fully guaranteed. Dealer inquiries welcomed. PDO
Electronics, Box 841, North Little Rock, Arkansas 72115.
INTEL 8008: $59.45; 8038: $5.95; 1101 RAM: $2.25; 1103
RAM: 54.50 2513, 2516: CHAR. GEN. ROMS: $12.75.
ELECTRONIC DISCOUNT SALES, 138 N. 81st St., Mesa,
AZ 85207.
TROUBLE getting parts for projects? Let us buy them for
you. Parts buying service. Box 1026-P2, Fremont, Calif.
94538.
GSIUBSCRIB.E NOW: 2C
' LEARN THE SECRETS OF YOUR TELEPHONE
u
1FACTS NEVER BEFORE PUBLISHED FOR THE PUBLIC
- One year subscription S 3.00 --Sample copy 251 -
TFLFTRONIC9 P.O. SO%0.96
r7 co.., OF AMERICA T C LOS ANGELES,CA 90099
BUGGED'"? Rid Electronic Snoopers. Countermeasure
Equipment Catalog $1.00. Security, Box 671, Westwood,
New Jersey 07675.
LIQUID CRYSTAL. 3-1/2 digit wristwatch display. New,
with instructions for building wristwatch. Final close-out.
Less than original, factory wholesale price. $5.50 each.
Two for $10. Tricounty-Winslow, Inc., Box 5885, Grand
Central Station, New York, N.Y. 10017.
CIRCUIT board service. Circuit boards made from your
layouts. Send for information. Printed Circuits, 22 Maple
Avenue, Lackawanna, New York 14218.
FIREPLACE heat exchanger. Use All Heat. Plans $3.00.
Jennell, 6030 O'Day Dr., Centreville, VA 22020.
LASER TUBE - $23.50; Five Laser Plans - $4.00; Catalog
- $1.50, "PE 1074", Plasma Scientific, Box 1005,
Claremont, Calif. 91711.
DIAGRAMS, Radio, TV. etc., $2.00. CIRCUIT design
service, request quotation. TECHSERVAS, Box 1167,
Berkeley, CA 94701.
SOLARWIND ... The New Sun Power - Wind Power News-
letter ... News, Theory, Experiments, Projects, Plans ...
Sample Copy $1.00. Ma mann Optics and Electronics.
Dept. K1, 836 South 113, West Allis, Wisconsin 53214.
ELECTRONIC COMPONENTS -all kinds, send for free
catalog. Epic, Box 20152A, Minneapolis, Minn. 55420.
ANTIQUE RADIO SCHEMATICS. Send SASE. Sterling, Box
202. 06878.
HIGH FIDELITY
DIAMOND NEEDLES and Stereo Cartridges at Discount
prices for Shure, Pickering, Stanton, Empire, Grado and
ADC. Send for free catalog. LYLE CARTRIDGES, Dept. P,
Box 69, Kensington Station, Brooklyn, New York 11218.
SAVE 50%. Build your own speaker systems featuring Nor-
elco, Eminence and CTS. Famous brands from world's lar-
gest speaker factories at lowest wholesale prices. Write for
free catalog of speakers and electronic accessories.
McGee Radio Company, 1901 McGee Street, Kansas City,
Missouri 64108.
WANTED
QUICKSILVER, Platinum, Silver, Gold, Ores Analyzed.
Free Circular. Mercury Terminal. Norwood. Mass. 02062.
PLANS AND KITS
TRIGGER SWEEP GENERATOR -improve your low cost
scope by adding solid state trigger sweep. Complete kit,
$20.00 PPD. Information Free. PHOTOLUME
CORPORATION, PO Box 139, New York, N.Y. 10016.
TESLA COIL -40" SPARKS! Plans $7.50. Information 75
cents. Huntington Electronics, Box 2009-P, Huntington,
Conn. 06484.
AMAZING ELECTRONIC PRODUCTS -Pocket Laser, See -
In -The Dark, Scramblers, Penlight Strobe, Energy Devices,
TV Disruptor, Many More, All New. Catalog $1.00.
INFORMATION UNLTD., West St., Milford, N.H. 03055.
PROJECT PLANS. New projects every month. Send for
complimentary copy. Electronic Projects Newsletter, Box
1026P, Fremont, Calif. 94538.
POWER supply plans, great for IC experimenters! 2
channel, each regulated 0-15 VDC at 1 amp, 55.00. Easy to
build, parts available from us. B&F Industries, 3603
Glenrose Ave., Altadena, CA 91001.
KITS
UNIQUE
CANADIAN
ELECTRONICS
CATALOGUE
S1.00
(refundable on lst purchase)
featuring
SINCLAIR hi-fi modules and calculator
kits. We will include the new 32 -page
Project 80 hi-fi module construction
manual.
AMTRON electronic kits -over 100 types!
Speaker kits and components
American enquiries welcome!
OLaDSTORE 1l5-ELECTROIlICS
1736 AVENUE RD.,TORONTO,ONT.
M5M 3Y7. DEPT. PE -11
^
HONEYWELL COMPUTER BOARDS
V ',ió ,, II L' - Ma Lirt. _ V
F9121 F9082
Two popular HONEYWELL computer boards, filled with many
types of components.Transistors, diodes, precision resistors and
capacitors,zeners, heat sinks trimmers etc. Some of the F9121
boards have MADT high Freq. transistors. 4'/."x12"
STOCK NO.F9121 3 boards $2.00 9 boards $5.00
STOCK NO.F9082 2 boards $1.00 12 boards $5.00
EXOTIC COMPUTER BOARD GRAB BAG
úát
ft mil,rtr11
4í4':t4/?rit JWiz
I oi,7;J !
a r ,`'..
r .+-;1 f
G.E., Xerox &
This lot of boards are the very latest from
other top manufacturers. These boards contain expensive
components, such as reed relays, SCRs, power transistors,
heat sinks, trimmers etc. All late (1973 & 1974) boards.
At least 1 part on each board is worth more than our price
for the entire board. We have seen boards in this lot with
as many as 9 reed relays. Money back is not 100% pleased.
STOCK NO.F9934 7 different boards $10.00, 21/25.00
HIGH POWER AMPLIFIER TRANSFORMER
This transformer is ideal for high power applications.Winding
1, 64 volts ct @8 amps, tapped at 32 volts ct. @ 8 Amps.
Winding 2 18 volts ct. @ 8 amps. Winding 3, 400 volts @ .15 A.
This transformer easily delivers over 500 watts. 4'/9"x4"x4".
STOCK NO.F9905 Wt. 10 lbs. $11.95 ea. 2/22.00
MINIMUM ORDER $5.00. Include postage, excess refunded. New
edition of our catalog now available.
A DELTAYNELECTRONICS
BOX 1. L. MASSACHUSETTS 01903 CO.
Phone (617) 388-4705
PRICES SLASHED ! !
Due to the huge success of our anniversary sale we
are extending the sale prices to December 21.
Our catalogues 25¢ Pa tzdabta. with. ls1. ord .r
POWER SUPPLIES. Use them in all your projects!
F0510 5v 1.5 amp. was $ 8.95 NOW Only $7.95
F1210 12v 1.5 amp. was $ 9.95 NOW Only $8.95
F1510 15v 1.5 amp. was $10.95 NOW Only $9.95
Predrilled epoxy board and all parts included except
transformer. Transformer PC -16 $4.60 extra.
\, Our unexcelled quality 5% carbon FILM %2
watt resistors now only .07c each, minimum of
5 each value. Get them while they last!!
All Electrolytic and film capacitors reduced 10%.
NEW ITEM!! We've got Hewlett Packard red
LEDs for only 39c each. Includes Panel mount-
ing hardware. T-13/4 size. Part no. 5082.
0 will
If you're serious about quality then you'll
want our 'new MAN71 series of displays. They
I,
are typically 50% brighter than the old MAN
f. 7 series. We've got them in Red, Yellow and
Green. All .3" char. ht. With each display we
include one HP 5082 panel indicator LED. $4.00.
We also have 3 sizes of display bezels and filters that
will fit most of your needs. Plus we have 7400 series
logic, transistors and many other Brand New first
quality parts and kits. NO C.O.D.'s please.
Mastercharge and Bank Americard Accepted.
Tracy Design Corporation
15870 Schaefer (373)
838 - zsoi Detroit, Mi. 48227
CIRCLE NO. 11 ON READERS SERVICE CARD
102 CIRCLE NO. 38 ON READERS SERVICE CARD
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AmericanRadioHistory.Com
LIVE 'IN THE :WORLD
OF' TOMORROW.... TODAY
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A.. BETTER. LIFE °
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° IIb
"FISH WITH THE
"400 POUNDER"
Massive 12 lb. permanent magnet lifts 400
lbs-most powerful we've ever sold. Provides
instant handle for easy, safe metal carry, great
for retrieving metal parts. Releases quickly
-lift pivoted side handle, sever magnetic grip!
Use for flame cutting, shearing, punching,
positive ground for welding; remote usage, etc.
Tie a line to it and go treasure hunting at sea! Powerful ceramic magnet lifts more
under water (best through 1" steel plate).
No. 85,238AV (131/2x5x5) $65.00 FOB.
4
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He-Ne LASERS FROM $99.50!
Edmund quality, TEMoo mode, cold cathode for
long life. Completely self-contained units; solid
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GREAT GENERAL PURPOSE LASER: 1.2mm
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Stock No. 7'9,061AV $99.50 Ppd. ,L ..+
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3.0mW min- DEPENDABLE HI -POWERED LASER: 1.0mm beam dia., 0.8mRad
beam Diverg.
Stock No. 79,052AV $325.00 Ppd.
. TAKE TEMPERATURES
IN SECONDS
Edmund's new electronic oral thermometer ob-
solete' glass mercury type. Seconds instead of 'r '
minutes, more accurate, much easier to read!
Put disposable cover (supply incl.) on flexible . ~MO
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doctors', nurses' shirt pocket. Inds 9v trans batt., instrs.
Stock No. 42,210AV $25.00 Ppd.
THE MOST POWERFUL
SOLAR CELLS
Price & technology breakthrough. Harness the
sun with these 2" dia. 500 mA@ .5V silicon cells
- 5 times more efficient per cost than ever
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No. 42,145AV ...(TAB LEADS) $11.50 Ppd.
No. 42,146ÁV ... (TAB LEADS) $7.95 Ppd.
.5V
No. 30,538AV ... (WIRE LEADS) $6.95 Ppd.
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164 PAGES MORE THAN
w N:
4500 UNUSUAL
I Completely new Catalog. Packed with huge selection of telescopes, mi.1
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Iecology and Unique lighting ,tems, parts, kits. accessories - many
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I EDMUND SCIENTIFIC CO.
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IR WAR SURPLUS
ELECTRIC GENERATOR
Brand new Signal Corps Model, Up to
90 volts by turning crank. Use in high
impedance relays. Charge ground &
bring up night crawlers for bait or
study. 2 Alnico Magnets alone now
worth more than original $15gov't cost.
No. 50,225AV .. (2 lbs.) $8.50 Ppd.
. MASSIVE NEW 576X
6" REFLECTOR
f = Great for astrophotography! Features 48" F. L.
f/8 Pyrex r0 parabolic mirror acc. to VA wave;
massive equatorial mount (usually found only
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drive w/ manual slow-motion control, de-
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Ramsden; Barlow to dbl & triple power. 24" wobble -free metal base.
No. 85,248AV (SHP. WT. 200 LB) $499.00 FOB
"FISH" WITH A MAGNET
Go treasure hunting on the bottom! Fascinating
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No, 71,135AV ... (31/2x3W) $17.50 Ppd.
75 -LB. PULL (1 LB.) W/ 3 CERAMIC MAGENTS
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AUTHENTIC SCALED
WINDMILLS
Real -thing replicas show wind direc-
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light, house number, sign or as mail-
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gauge steel, durable outdoor finish; aluminum color w/red trim.
No. 71,923AV (17" DESK MODEL) $10.95 Ppd.
41 FOOT - 14 LB. No. 71.924AV $32.50 Ppd.
8 FOOT - 46 LB No. 85,229AV $44,95 FOB
130 EXPERIMENTS IN OPTICS , , ,
and photography! Optix® Experi-
ments Kit is a complete optical and
photography lab for 130 exciting ex-
periments. Lets you recreate the peri-
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oscope! Build a 35mm reflex camera
with interchangeable lens system!
Make, develop photographic film! En-
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illustrated 112-pg. manual, 81/2 x 11", clearly explains usage of
this stimulating kit's 114 precision engineered components.
Stock No. 71,646AV $24.95 Ppd.
AERONAUTICS FUN KIT (100 Experiments)
Stock No. 71,840AV $15.95 Ppd.
imooóli.
COMPLETE 8 MAIL: WITH -_CHECK 'OR -M-,O:
EDMUND SCIENTIFIC CO. 300 Edscorp Building, Barringtoe, N.J. 08007
O PLEASE SEND
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TOTAL S
NAME
ADDRESS
I
L,ty Stale p
NOVEMBER 1974
I - CITY
Mai - - - - - al tOr ~ log
CIRCLE NO. 15 ON READERS SERVICE CARD
STATE el
105
AmericanRadioHistory.Com
SCORE high on'F.C.C. Exams...Over 300 questions and
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Second Test, $14.50; First Class Test, $15.00. All tests.
$26.50. R.E.I., Inc., Box 806, Sarasota, Fla. 33577.
LEARN design techniques. Electronics Monthly
Newsletter. Digital, linear construction projects, design
theory and procedures. Sample copy $1.00. Valley West.
Box 2119-B, Sunnyvale, California 94087.
FCC LICENSE through tape recorded lessons. Also Radar
Endorsement. Radio License Training, 1060D Duncan,
Manhattan Beach, Calif. 90266.
LEARN ELECTRONICS at home. FCC license, Communi-
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Catalog. Genn, 5540 Hollywood BV., Los Angeles, CA
90028.
MUSICAL INSTRUMENTS
30% DISCOUNT name brand musical instruments. Free
Catalog. Freeport Music. 455N, Route 110, Melville, N.Y.
11746.
WHOLESALE! Professional Guitars, PA Systems. Altec
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30%+DISCOUNT. Name Brand Musical Instruments. Free
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SPECIAL interest records available, produced by the
editors of the world's leading special interest magazines.
Send for free catalog. Record Catalog, CL, Ziff -Davis
Publishing Co., One Park Avenue, New York, N.Y. 10016.
BUSINESS OPPORTUNITIES
I MADE $40,000.00 Year by Mailorder! Helped others make
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FREE CATALOGS. Repair air conditioning, refrigeration.
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MAILORDER MILLIONAIRE helps beginners make $500
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FREE Secret Book "2042 Unique Proven Enterprises."
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$200.00 DAILY In Your Mailbox! Your opportunity to do
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ALTAJ ELECTRONIC BARGAINS
CALCULATOR CHIP BONANZA!
THREE VERSIONS TO CHOOSE FROM
Never before offered in USA. These are the
newest and easiest to use chips available to
the hobbyist today. Features: direct segment
drive for LED's, low power consumption,
single supply voltage, internal encoding of
keyboard inputs, internal keyboard debounce,
internal clock oscillator. Made by famous US
mfg. No one but ALTAJ offers calculator
chips with these sophisticated functions. All
are 28 Pin DIP. with specs. FLOATING DEC.
CHIP #1 - 8 DIGIT READOUT, CONSTANT,
SIX FUNCTION (+ , -, x, _ , %, ') - $7.95
CHIP #2 -8 DIGIT READOUT, MEMORY, SIX
FUNCTION (+,-,x, =,r-,nr)-$8.95
CHIP #3 - 8 DIGIT READOUT, MEMORY,
SIX FUNCTION (+, -, x, - , %, 1/x) - $8.95
SOLID STATE MEMORY ARRAY
Brand new, MFG. by Monolithic
Systems Corp. Consists of 16-1101
(256 Bit Ram) and associated drive
circuits. Drive circuits include 24
assorted 7400 series devices and
various transistors, diodes, etc.
Array is mounted on two stacked 6 x
8 in. PC boards. Original cost $300
ea. With schematic. These 'are
recommended for experienced
hobbyists only. Limited quantity -
$29.95 ea.
3 DIGIT LED READOUTS
Perfect for use with our calculator chips. 3
MAN -3 Readouts in one DIP. Properly multi-
plexed. New prime units. Like Litronix DL -33.
$1.25 ea. 3 for $2.95
FACTORY NEW LED'S - SALE!
Jumbo Red -Like MV5024 - 8
for $1
Jumbo Green -Like MV5222 - 5
for $1
Mini Red -Like MV50 - 10 for
$1
PC BOARD SPECIAL #3
Boards from computer eqmt. with the follow-
ing items: 1-3.600 MHz Oscillator 5 VDC,
2 -Monsanto MCT2 Opto Isolator, 4-2N3642
Transistors, 1-2N2646 Unijuction, 2-7400,
1-7402, 1-7404, 2-7408, 1-7410, 1-7438,
1- 7474, 2-7476, 1-7486, 3-7490, 1-7492,
3-7493, 1-74164, 1-74165, 1-74180, 1-9601
Plus 17 other DIP IC's. Limited quantity.
Special Price - $4.95
OPCOA SLA-1 LED READOUT
.33 in. Character. Left DEC. point.
Uses 7447 driver. Easier to read than
MAN -1 types. Factory prime units
$1.19 ea.
REGULATED DC POWER SUPPLY
Brand new mfg. by WANLASS. Open Style.
DC Output 17 to 30 V. Rated 60 watts. Our
tests show these units will put out 12 VDC by
changing one resistor. Wanlass #OEM60-3.
Original cost $57.50. In original factory
boxes, with specs and schematic. Special -
$19.95
DIGITAL ALARM CLOCK IC
Through a special arrangement with
a famous U.S. MFG. we can offer
these MOS chips. This is the newest
and easiest to use alarm chip on the
market today. Features: 1. Single
supply voltage
2. Led intensity control
3. Simple time set
4. 4 or 6 digit led display
5. AM -PM indication
6. 24 hr alarm with 10 min.
snooze
7. Outperforms MM5316
COMPARE THIS PRICE - $7.95 ea.
WITH SPEC. SHEETS
5178.00 WEEKLY. Work. one hour daily. Free brochure.
FAS, Box 13703-A, San Antonio TX. 78213.
CITIZENS BAND
' DEALER -DISTRIBUTORS
Send this Ad to:
PAL ELECTRONICS CO.
P. O. Box 778 Westminster, Ca. 92683
EARN $15,000 annually plus. Full year trial plan Import-
Mailorder business. Postcard brings details: Northeast
Imports, Box 121PE10. Fremont, N.H. 03044.
HOW TO SELL BOOKS BY MAIL. FREE INFORMATION
McCord. Box 276-D. SYLVANIA. OHIO 43560.
$1,000 MONTH Mailorder. Send Stamp. Fiddes. Box 1242F
Glen Burnie, MD 21061.
OPPORTUNITY PACKAGE! Three amazing business plans
Free details; Gray Bros., 4830 Só. 137 St., Suite 72U -t 1
Omaha, Nebraska 68137.
. EARN :$ '500 WEEKLY °
OR MORE - EASYI
Now needed - Vinyl Repair Specialists/Dealers!
Sensational opportunity available! Operate your
own profitable business. Write today!
FREE GT PRODUCTS. INC.. Dept H K
SAMPLE & 6156 Mission Gorge Ro.
DETAILS San Diego. Calif. 92120 L.
JUMBO LED READOUT
.65 in. character. Twice the size of regular
readouts. Like Litronix DL747. Outperforms
SLA-3. Easy to read. Draws only 20 MA per
segment. Perfect for giant digital clocks.
$2.95 ea.
AC LINE CORDS
7 Ft. Black. 2 wire. 4 for $1
FAIRCHILD STYLE VOLTAGE
REGULATORS
1 AMP Output - Your Choice - $1.25
Ea.
7805 - 5VDC 7815 - 15VDC
7806 - 6V DC 7818 - 18V DC TO -220
7812 - 12VDC7824 - 24VDC CASE
HOBBYIST LINEAR SPECIAL
We bought too many too test. Includes many
useable devices. Buy untested and save.
LM380 2 watt audio AMP 8 for $1
LM3900 QUAD OP AMP 8 for $1
709C OP AMP - 10 for $1
741C Mini DIP OP AMP 10 for $1
RCA STYLE - C-MOS IC'S - NEW!
CD4001 - 44c CD4016 - 89c
CD4002 - 44c CD4020 - 1.49
CD4011 - 44c CD4049 - 49c
CD4013 - 95c
MINI CORE MEMORY SYSTEM
Mfg. by Dataram. Stores 180 words of 18 bits
each. With sense AMP's and associated
electronic drive circuits. A complete memory
system. We include 50 pages of data and
schematics. BRAND NEW - $24.95 Data
Only $2.50
7400 SERIES STYLE - C-MOS
74C04 - 49c 74C83 - 1.25
74C107 - 95c
LM 309K - 95c
1 AMP 5VDC TO -3 Voltage regulator new
by national. Prime units.
MALLORY FILTER.CAPS
2000MFD 30VDC - 39c SMALL SIZE
ALTAJ ELECTRONICS
P.O. BOX 38544
DALLAS, TEXAS 75238
TERMS: Check or M.O. No COD.
Add 10% for PSTG and HDLG. Tex.
Res. .Add 5%
NOVEMBER 1974 CIRCLE NO. 2 ON READERS SERVICE CARD 107
AmericanRadioHistory.Com
IF YOU CAN SOLDER, YOU CAN
BUILD YOUR OWN
Clock/Ca en gar
SOLD Súz1L SYSTIMS0 Onto has available a
CLOCK/CALENDAR kit containing over 120 separate electrical
components.
The clear, simplified instructions include step by
step construction procedures and ample illustrations
which will quickly take you through construction of
this versatile Clock/Calendar.
THE KIT FEATURES:
* DISPLAY OF DATE WITH MONTH AND DAY -
displays month and day automatically, through
year, except for February 29.
* DISPLAY OF TIME ON 12 HOUR CYCLE - hours
and minutes displayed with A.M. and P.M.
indicators.
* A 24 HOUR ALARM OPTION - this also includes a
snooze button which delays alarm an additional 10
minutes.
* A 9 HOUR 59 MINUTE TIMING OPTION - this
allows operation of any pluggable 600 watt, 120
volt, 5 amp, 60 Hz electrical device such as a radio,
room light, stereo or coffee pot.
* EASILY VISIBLE SPERRY® DISPLAY - this
display is highly visible in a well lighted room.
An attractive case may be fabricated of wood,
plexiglas, metal or whatever you feel would make an
appropriate show -case for your finished kit.
TO ORDER:
' stY car . or.
PLEASE NOTE: These kits do not include cases.
This kit when completed is a sophisticated device
which offers many additional features due to its
flexibility, here are two examples of what can be
done with this device:
1. You may set the timer to play your radio for 15
minutes at bedtime, then the alarm allows you the
option of waking up to the radio in the morning all
automatically.
2.You may set the alarm to later start an appliance
which will operate for the duration of the setting
on the timer.
Order Number 01-12241 - BASIC CLOCK - This kit does not include the 24 hour alarm option or the 9 hour 59
minute appliance timer option. Price $49.95
Order Number 02-12241 - COMPLETE CLOCK - This kit includes all available options. Price $65.00.
ti
11 O,NQo 800-325-2981 - 800-325-2983
SEND YOUR ORDERS TO:
SOLID STATE SYTEMS, INC.
P. O. BOX 617
COLUMBIA, MISSOURI 65201
OR PHONE (TOLL FREE)
BwNKAMERICAR6
master charge
E
NOVEMBER 1974 CIRCLE NO. 36 ON READERS SERVICE CARD 109
AmericanRadioHistory.Com
FREE IC
With Every $10 Order*
REDUCE YOUR PROJECT COSTS
MONEY -BACK GUARANTEE
24 -HOUR SHIPMENT
ALL TESTED AND GUARANTEED
TRANSISTORS:
NPN:
2N3563 TYPE RF Amp & 0SC to 1 GHz (pl. 2N9181
2N3565 TYPE Gen. Purpose High Gain (TO -1061
2N3567 TYPE High -Current Amplifier/Sw 500mA
2N3691 TYPE GP Amp to 25mA and 50 MHz
2N3866 TYPE RF Pwr Amp 1-2 W @ 100-600 MHz
2N3903 TYPE GP Amp & Sw to t00mA and 30 MHz
2N3904 TYPE GP Amp & Sw to 100mA (T0921
2N3919 TYPE RF Pwr Amp 3-5 W @ 3-30 MHz
2N4274 TYPE Ultra -High Speed Switch 12ns
MPS6515 TYPE High -Gain Amplifier hFE 250
Assort. NPN GP TYPES, 2N3565, 2N3641, etc. 115)
PNP:
2N3638 TYPE Gen. Purpose Amp & Switch
2N4249 TYPE Low -Noise Audio Amp 10A to 50mA
FET's:
N -CHANNEL (LOW -NOISE):
2N4416 TYPE RF Amplifier to 450 MHz (70.721
2N5486 TYPE RF Amp to 450 MHz (plastic 2N4416I
2N5163 TYPE Gen. Purpose Amp & Sw (T0.106)
254091 TYPE RF Amp & Switch (TO -106)
E100 TYPE Low -Cost Audio Amplifier
ITE4868 TYPE Ultra -Low Noise Audio Amp.
TIS74 TYPE High -Speed Switch 400
Assort. RF & GP FET's, 2N5163, 2N5486, etc. 181
P -CHANNEL
2N4360 TYPE Gen. Purpose Amp & Sw (TO -106)
E175 TYPE High -Speed Switch 1250
M104 TYPE MOS FET (Diode protected) 0.3 pF
LINEAR IC's:
309K Voltage Regulator 5V @ lA (70.31
380 2-5 Watt Audio Amplifier 34dB (DIP)
555X Timer los -1 hr, Dif. pinout from 555 (DIP)
709 Popular OP AMP (DIP/TO.SI
723 Voltage Regulator 3-30 V @ 1-250mA (DIP/TO-51
739 Dual Low -Noise Audio Preamp/OP AMP (DIP)
741 Freq. Compensated OP AMP (0IP/T0.5/MINIOIP)
2556 Dual 555 Timer 1 sasec to 1 hour (DIP)
LM305 Positive Voltage Regulator (T0-51
MC1458 Dual 74t OP AMP (MINI -DIP)
Assorted Linears-741/789/723, etc. (4)
DIODES:
1 N914 TYPE Gen. Purpose 100V/10mA
1 N3600 TYPE Hi Speed SW 75V/200mA
1 N4608 TYPE GP & SW 80V/400mA
1N3893 TYPE RECTIFIER Stud Mount 400 V/12 A
1N749 ZENER 4.3 Volt 400mW
15753 ZENER 6.2 Volt 400mW
1N755 ZENER 7.5 Volt 400mW
1N757 ZENER 9.1 Volt 400mW
1N758 ZENER 10 Volt 400mW
15965 ZENER 15 Volt 400mW
15968 ZENER 20 Volt 400mW
D5 VARACTOR 5-50 W Output @ 30.250 MHz, 7-70 pF
F7 VARACTOR 1-3 W Output @ 100-500 MHz, 5-30 pF
6/S1.00
6/51.00
3/S1.00
6/S1.00
S1.50
6/51.00
5/$1.00
$3.00
4/51.00
3/$1.00
$2.00
4/51.00
4/S1.00
2/S1.00
3/S1.00
3/$1.00
3/S1.00
4/$1.00
2/$1.00
3/$1.00
$2.00
3/51.00
3/S1.00
S3.00
51.90
51.50
S .90
S .39
$ .75
$1.00
$ .45
51.55
$1.25
$ .95
S2.00
10/S1.00
6/51.00
6/51.00
2/S1.00
3/$1.00
4/$1.00
4/$1.00
4/$1.00
4/$1.00
4/$1.00
4/$1.00
$5.00
51.00
MAIL NOW! With every order of $10 or more, postmarked
prior to 12/31/74. FREE 739 or 749 Low -Noise Dual OP AMP
included -$1 VALUE.
ORDER TODAY -All items subject to prior sale and prices subject
to change without notice. DATA SHEETS Included with all items.
WRITE FOR FREE CATALOG offering hundreds of semi.
conductors not listed here. Send 100 stamp.
TERMS: All orders prepáid. We pay postage. $1.00 handling
charge on orders under $10. Calif. residents add 6% sales tax.
A DVA ELECTRONICS
BOX 4181-J, WOODSIDE, CA 94062
Tel. (415) 851-0455
CIRCLE NO. 1 ON READERS SERVICE CARD
TREASURE FINDERS
FAMILY FUNI OUTDOOR ADVENTURE! Find valuable
coins and treasure with world famous metal detectors. Free
illustrated booklet. Detectron, Dept. PE, Box 243, San
Gabriel, Calif. 91778.
TREASURE FINDER locates buried gold, silver, coins.
treasures. 5 powerful models. $19.95 up. Instant financing
available. Free catalog. Dealer inquiries invited. Relco,
Dept. A-33, Box 10839. Houston. Texas 77018.
ELECTRICAL SUPPLIES & EQUIPMENT
PLATING Equipment, Portable Platers, Supplies and
"Know -How." Build your own tanks for nickel, chrome,
etc. Easy -to -install PVC liners. Rectifier components -all
sizes. Schematics, parts lists, formulas, operating
instructions for all plating. Guaranteed to save you 25%-
75%. Some good units for sale. Write for details. Platers
Service Company, 1511 -PE Esperanza, Los Angeles, Calif.
90023.
MAGAZINES
CRAFT AUDIO
isn't a lost art. Readers of the
Audio Amateur magazine are cus-
tomizing and scratch building their
equipment with gusto and great re-
sults. Free prospectus tells all.
Box 30P Swarthmore PA 19081
MOVIE FILMS
8MM-SUPER 8-16MM MOVIES! Biggest Selection! Lowest
Prices! Free Catalog! Cinema Eight. Box PE. Chester,
Connecticut 06412.
EMPLOYMENT OPPORTUNITIES
ELECTRONICS/AVIONICS EMPLOYMENT OPPORTUN-
ITIES. Report on jobs now open. Details FREE. Aviation
Employment Information Service, Box 4240E. Northport,
New York 11768.
EMPLOYMENT INFORMATION
JOBS, Electronic Technicans, EE's, Tech Reps. Address
100 companies. US and overseas. Send S2.00. Marshburn,
Box 655, Wylie. Texas 75098.
REAL ESTATE
BIG...FREE...CATALOG! 272 pages! Over 2,500 top
values in FARMS, RANCHES, ACREAGES,
RECREATIONAL PROPERTIES, BUSINESSES, TOWN and
COUNTRY HOMES in 40 states coast to coast! Over 3,800
PHOTOS! UNITED FARM AGENCY, 612 -EP West 47th St.,
Kansas City, MO 64112.
RECORDS
OLDIES. 45rpm. Free Catalog. Corny's Record Shop, Box
335TP, Mason, Ohio 45040.
RUBBER STAMPS
RUBBER address stamps. Free catalog. 45 type styles.
Jackson's. Box 443G, Franklin Park, III, 60131.
MAGNETS
MAGNETS. All types. Specials -20 disc, or 10 bar, or 2 stick,
or 8 assorted magnets, $1.00. Magnets, Box 192-H,
Randallstown, Maryland 21133.
DO-IT-YOURSELF
FREE WINDPOWER HEAT Cuts fuel bills, beats shortages.
Encyclopedic windmill/generator report gives sources.
costs, instructions, capacities, specifications. Now $2.98
from Energy Unlimited, Dept. 611, 219 Thorndike Street,
Palmer, Mass. 01069.
PLASTICS
CASTOLITE pours like water, hardens like glass without
heat. Crystal clear, colors. Embed flowers, seashells,
mementos, anything. Make fine gifts. Form flexible molds
over any pattern, size. Reproduce your own designs in
plastics, candlewax, metal, plaster, cement. Send 50 cents
for illustrated Manual and New Mold Catalog. Profitable.
CASTOLITE, Dept. 74M/PE, Woodstock, III. 60098.
HYPNOTISM
SLEEP learning. Hypnotic method. 92% effective. Details
free. ASP Foundation, Box 23429EG, Fort Lauderdale,
Florida 33307.
FREE Hypnotism. Self -Hypnosis. Sleep Learning Catalog!
Drawer H400, Ruidoso, New Mexico 88345.
AMAZING self-hypnosis record releases fantastic mental
power. Instant results! Free trial. Write: Forum (AA11), 333
North Michigan, Chicago 60601.
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r,w-AFFIX LABEL -a, ,
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110 POPULAR ELECTRONICS
AmericanRadioHistory.Com
Popular Electronic
NOVEMBER 1974
ADVERTISERS INDEX
READER
SERVICE NO. ADVERTISER
PAGE
NUMBER
1 Adva Electronics 110
Allied Electronics 91
Alpha Electronics 26
2 Altaj Electronics 107
Ancrona Corp 13
44 Audioanalyist, Inc 71
3 Audio-Technica U.S., Inc 16
6 68K Products of Dynascan
Bell & Howell Schools 18 19, 20, 21
CREI Capitol Radio Engineering
Institute
7 Cleveland Institute of
Electronics Inc 62 63, 64, 65
8 Clifford's Hi -Fi Wholesalers 87
9 Cobra Product of Dynascan Corporation 23
10 Continental Specialties Corp 81
11 Delta Electronics Co 102
12 Delta Products, Inc 15
13 Digi-Key Corporation 111
14 EICO 89
15 Edmund Scientific Co 105
16 Edmund Scientific Co 112
GC Electronics 98
17 GTE Sylvania 28 29, 30, 31
18 Great American Sound Company, Inc., The 7
19 Greenlee Tool Co 96
5 Heath Company 72 73, 74, 75, 76, 77
20 Illinois Audio 80
21 International Electronics Unlimited 99
22 James Electronics 100
33 Johnson Co., E.F. 6
23 Kroch's & Brentano 's 1
24 Lafayette Radio Electronics 97
26 McIntosh Laboratory, Inc 81
27 MITS, Inc 96
28 Midwest Hifi Wholesale 24
NRI Schools 8 9 10, 11
82 83, 84, 85
National Technical Schools
5
92 93, 94, 95
29 Olson Electronics 17
45 Phase Linear Corporation 14
30 Pickering & Co 2
31 Poly Paks 101
32 Radio Shack THIRD COVER
34 SAE, Inc 16
46 Shure Brothers Inc 27
35 Solid State Sales 106
36 Solid State Systems, Inc 108, 109
37 Southwest Technical Products Corp 67
38 Tracy Design Corporation 102
39 Tri-Star Corp 6
40 Trigger Electronics 87
41 U.S. Pioneer Electronics Corp SECOND COVER, 1
4 United Audio Products, Inc FOURTH COVER
42 Utah Electronics 25
43 Vl Products 17
Vintage Radio 24
Warehouse Sound 12
CLASSIFIED ADVERTISING ...99, 100, 102, 106, 107, 110, 111
HOME ENTERTAINMENT FILMS
COLOR ACTION SPORTS FILMS (Also B& W) - make
great gifts in Super 8 and Standard 8. Treat yourself - a
friend. In color. 516.95 each plus 50 cents postage; 57.95
plus 50 cents B&W for 200' reel. Select from Columbia,
Castle and Sponlite Catalogs at 25 cents each (stamps or
coins, please). Be on time for Christmas, send your
quarters today. SPORTLITE, Elect -11 Dept., 20 North
Wacker Drive, Chicago. Illinois 60606.
TUBES
RADIO & T.V. Tubes -36 cents each. Send for free
Catalog. Cornell. 4213 University. San Diego, Calif. 92105.
RECEIVING & INDUSTRIAL TUBES, TRANSISTORS. All
Brands - Biggest Discounts. Technicians. Hobbyists.
Experimenters - Request FREE Giant Catalog and SAVE!
ZALYTRON. 469 Jericho Turnpike , Mineola, N.Y. 11501.
TUBES receiving, factory boxed, low prices, free price list.
Transleteronic. Inc., 1306 40th Street. Brooklyn. N.Y.
11218A, Telephone: 212-633-2800.
TUBES "Oldies', latest. Lists free. Steinmetz, 7519
Maplewood, Hammond, Indiana 46324.
TUBES 60% OFF LIST PRICE. McCord Electronics, Box
276-T, Sylvania. Ohio 43560.
BOOKS
FREE catalog aviation/electronic/space books. Aero
Publishers, 329PE Aviation Road, Fallbrbok, California
92028.
FREE book prophet Elijah coming before Christ. Wonderful
bible evidence. Megiddo Mission, Dept. 64. 481 Thurston
Rd., Rochester. N.Y. 14619.
BOOKS -thousands titles, bargains. Catalog Free.
Casslano, 92-27 New York Blvd., Jamaica, New York
11433.
UNUSUAL BOOKS! Catalogue Free! International Imports,
Box 7789PE, Atlanta, Georgia 30309.
LEARN RADIO ANNOUNCING! Books, Magazines: Deejay,
Box 1355-C, Sioux Falls, South Dakota 57101.
POPULAR ELECTRONICS INDEXES, Detailed and
complete subject indexes now available to both 1972 and
1973 magazines. Hundreds of subject references to help
you quickly find that special project, article, or product
test. 1972 and 1973 editions 51.00 each. INDEX, box 2228,
Falls Church, Va. 22042.
INSTRUCTION MANUALS -Thousands available for test
equipment, military electronics. Send $1.00 (Refundable
first order) for listing. A service of Tucker Electronics, Box
1050, Garland. Texas 75040.
MISCELLANEOUS
WINEMAKERS: Free illustrated catalog yeasts, equipment.
Semplex, Box 12276P, Minneapolis, Minn. 55412.
NATIONAL TATTOO SUPPLIES send $3.00 for our catalog.
P. 0. Box 2063. New Hyde Park, New York 11040.
' 1975 Electronic Experimenter's Handbook- '
414 ` . Winter Edition
I This latest edition helps you get it
.1 . -I together with a score of mind -ab-
sorbing, build -it -yourself projects -
all with complete construction plans,
including parts lists and printed -
circuit board patterns, Many products
are unique designs, not available
anywhere else. And in all cases, you
save money by'building your own!
1975 Winter Edition $1.25 3146.
Back issues available: 1974 Spring $1.25 #41, 1974
Winter $1.25 #64, 1973 Spring $1.25 #2, 1971
Winter $1.50 4133, 1970 Spring $1.50 #14.
Order by number from
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$2.50 per copy, postpaid.)
(PAYMENT MUST BE ENCLOSED WITH ORDER°
FREE i; Spectacular sound! Stereo testing!
Background music and sound effects!
SPECIAL Special Interest Records available
INTEREST exclusively from Ziff -Davis.
RECORD Send for your tree Record Catalog -
CLQG Ziff -Davis Publishing Co., Dept. 23,
CATOne Park Ave., New York, N.Y. 10016.
EN916... 70.106
E52222.. T0.106
2N2712.. 0. 96
2933910. '0. 96
253393.. '0- 98
203563.. 10.106
293636.. 10-105
253640.. "0106
253643.. T0.105
2213646.. "0406
203906.. EO. 92
254126.. 10- 92
274103.. 10 92
205089.. T0. 92
255133.. 00.106
2115137.. 10.106
25s139.. 10.106
Quality
Electronic Components
MINIATURE ALUMINUM
ELECTROLYTIC CAPACITORS
- AXIAL LEAD TYPE -
1 UFD/5GV 14c
2.2 UFD:30V . . 14c
3.3 UFDr35V . . 14c
4.7 UFD/35V 14c
10 UFD/'6V 14c
10 UFD/25V 14c
22 UFD/16V.. 14c
22 UFD/25V. . . 15c
33 UFD/'6V . . . 15c
33 UFD/25V 17c
47 UFD/16V 17c
lo 100
12c ltc
12c llc
12c tic
12c tic
12c tic
12c tic
12c tic
13c 12c
12c Itc
13c 12c
14c 13c
I lo 100
100 UFD/16V . .. 19c 15c 14c
100 UFD/25V . . . 24c 18c 17c
220 UFD/16V . . 24c 18c 17c
220 UFD/25V . . . 35c 25c 24c
330 UFD/16V ...35c 25c 24c
330 UFD/25V . . . 44c 35c 32c
470 UFD/16V . . . 37c 30c 27c
470 UFD/25V . . . 49c 39c 35c
1000 UFD/16V .. 49c 39c 35c
1000 UFD/25V ..75c 60c 55c
2200 UFD/16V .. 75c 60c 55c
47 UFD/25V.... 19c 15c 14c
SILICON TRANSISTORS
011 lea 1
.21 1185 .165 E5930.. T0.1o6 .21
.21 .185 .165 E1023690 10.106 .21
.18 .160 .145 EN2907. 70.106 .21
.72 .190 .175 2193192.. TO. 96 .22
.22 .190 .175 753394.. TO. 96 22
.70 .175 .160 253565.. 10.100 .20
.20 .175 .160 253636A. T0.105 .20
.22 190 .175 253641. 10.105 .20
.20 .175 .160 253645.. TO -105 .20
.22 .190 .171 253904.. T0 92 .25
.25 .225 .200 2194124 . T0. 92 .21
.27 .240 .770 254401.. TO 92 .32
.37 .790 .260 755087 . 10 92 .17
.77 .240 .220 2915129. 10.106 .19
.19 .170 .150 205134, . 10.106 .19
.19 .170 .150 255138.. 10.106 .19
.19 .110 .150 253055.. TO. 3 1.35
.185 .165
.185 .165
.185 .165
.190 .175
.190 .175
.175 .160
.175 .160
.175 .160
.175 .160
225 .200
.740 .220
.290 .260
.240 .220
.170 .150
170 .150
.170 150
1.30 1.09
FIELD EFFECT TRANSISTORS
M74102 . 90. 97 .44 .380 .350 255457.. TO- 92 A7 020 .375
NPN DARLINGTON TRANSISTOR
6895.013. TO.
&92
M. DC Curren. Gain of 5.000 01 IOmA. 36 320 .290
, 45/2 1/4 WATT CARBON COMP.
RESISTORS
5 each of the 85 standard 10% values (2.2-22M) %t W Resistors
(425 pcs-) Sorted by value S12/set 2-4 ore S11/set 5.9 ore 510/set.
5 each of the 70 standard 10% values (10-5.6M) 'l. W Resistors
(350 pcs_) Sorted by value 512/set 2.4 ore S11/set 5-9 are 510/set.
I!0.0í11n ,,u , 00ílld,. i4,rrid,á,q,. , 7h,r 0..00!(117111.
In- inL.. .. 189 u
89(8 P, ti 3011 ,5189,. 1, II ,, 6 blvdvl
l ,
,tul.! J
tf- I. ..P,rifirutinn í!30n.
25 V. DISC CAPS 5=©©
Value 1 10 100
.001.... 5c 3.5c 3c
.022 6c 4c 3.5c
.047.... 6c 4c 3.5c
.047.... 9c 6c 5.3c
.1 12c 9c 7.5c
LEE -APOLLO
DISPLA Y
$5.00
CI 5 V. common 9
pin tube base
IC SOCKETS
8 Pin DIP Solder 35c
éÉ0 14 Pin DIP Solder 45c
16 Pin DIP Solder 50c
VOLTAGE REGULATORS R 1
$ 1.80 ea. d
1129 5V 600mA .t1
1130 12V 500mÁ .11
1131 15V 450mA
Litronix 1100 Calculator
PRICE
S29.95
24 Pin DIP Solder 51.25 ',....-17.,
LINEAR INTEGRATED CIRCUITS
555 Minidip TIMER ... 51.00 10/1 9.50 565 DIP MI 53.57 10/130.00
567 Minidip TON DECODER 558 Minidip DUAL OF AMP
53.57 10/530.00 804 10/5 7.50
723 Dip VOLTAGE REG 51.15 101510.00 741 Minidip OP AMP... 504 10/5 4.51
747 Dip DUAL OP AMP 51.10 10/570.50 748 Minidip OP AMP... 000 10/S 5.50
DIGITAL TTL
74075 .. 32t
74015 . 32c
/4020 . 32c
14030 .3ac
7400, 35c
74051 . 35c
740611 .52c
14070 S2c
14061 3nc
740... 3.
741101 ..32c
741111..35c
74131 . 636
14161 506
74175 . 50c
14165 35c
7470N 324
74234 /5c
7426,1 360
743W 37c
ION
204
26
,64
284
311
31,
44,
324
324
11,
31,
56c
<4,
44
414
26
616
s
7437N SI, 46,
'4311 51, 464
<á, 32, 26
7<414. 51.45 51.77
14421.1. 11.20 s107
744511 5102 5144
744764. 11.30 5110
74476.51.30 S110
7440/1. 51.35 5115
lata.. 324
145114 . .32,
745314...324
7454,4 . .32,
145041 .. 32c
14607 .. 324
14100 .. 34x
747...400
14131 . 52c
7474N . 52c
7475N ..85,
284
724
334
35c
454
75,
124
1476N .. 604 Sk
74804 . . 74, 65c
746)14.51 07 91c
744301. 51.51 51.40
1486'4 . .601 57t
1489N.54.S0 S<00
74994 85c 724
74911 111/ 51.22
14910 .85c 72,
74931 05, 12,
74901.5170 5107
/40511. 61.70 51.07
740611. 51.20 51.07
741510 . 5Y 501
741210 . 70) DR
1411111 . 174 424
14123011.11 99c
741019 51 61 51 43
741501151 S6 51 30
741515s120 S1.01
741530 51.58 51<0
741S4N 5125 5100
74159111.44 51.19
74156.51J7 41.04
741511151.16 S1.30
74151451,56 51.19
7414#, 514S 51.74
74161151.95 51.14
14102N 51.95 5114
141434 51.05 11.74
1416<41145 51.74
7416511 51.4e 11.20
1414445703 51.80
/418á45I.20 51.01
741810 53.38 53.00
74182551/7 51.04
10192451/0 51.60
74193151 10 5160
741964f2.75 5141
'419.3110 51.47
Send for Free Catalog or Mail Readers
Service Card
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CALL 278.681.6674
Orders less than 510.00 add 50c Service Charge -Others Postpaid
..!7/1(11 rrulí41' (.0711/ 11031 ,0171:..
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CIRCLE NO. 13 ON READERS SERVICE CARO
111
NOVEMBER 1974
AmericanRadioHistory.Com
LIVE IN IN THE WORLD
OF TOMORROW: TODAY!
And our FREE 164 PAGE CATALOG is packed.
with exciting and unusual values in ecological and
physical science items - plus 4,500 finds for fun,
study or profit .. ;for every member of the family.
A BETTER LIFE
STARTS ,HERE
LIE DETECTOR TYPE METER
Amazing Emotion Meter reveals hid-
den likes, dislikes. Easy to use; sen-
sitive, accurate. Measures changes in
body resistance caused by changes
in emotional state. Needle movement
indicates emotional response (not
whether favorable or unfavorable).
Effectiveness depends on questions asked and interpretation. Unique 10 -oz.
set ideal for entertainment and education - parties, science projects,
psychological experiments. Requires 9V transistor battery (not included). In-
structions.
No. 42,1974AV (27/ x 4 x 13/41 $19.95 Ppd.
LOW-COST ULTRASONIC CLEANER
Full pint capacity at price of old
1/3 pt model. For home, industry!
Makes grimy, small delicate parts &
objects sparkle - from diamonds
to dentures, electronic items to coins
& combs. Fully transistorized metal
& stainless steel cabinet (6 x 4 x 4") ;a
with built-in tank has frequency control, item platform. Incls. cleaning powder,
mfrs. 1-yr guar. 110-120v AC.
Stock No. 71,003AV $65.95 Ppd.
No. 71, 198AV
#85, 128AV (33 lb.)
oEs SHMg9
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NEW! KIRLIAN PHOTOGRAPHY KIT!
Experiment in the fascinating new
field of "Kirlian electrophotography-
images obtained on film without
camera or lens by direct record-
ing of electric charge transmitted by
animate & inanimate objects. Each
"aura'' differs-animate aura said to
change corresponding to physical changes. Kit incls. portable darkroom, double
transformer isolated from power source; instrs.
Stock No. 71,938AV $49.95 Ppd.
"HIGH VOLTAGE PHOTOGRAPHY" by H.S. Dakin
No. 9129AV. (60 -PG. PAPERBACK BOOK) $5.00 Ppd.
11/4 Qt. Sz. $115.00 Ppd.
111 Gal. Sz. $299.50 FOB
"POP" YOUR OWN BUTTONS
Make customized badges in minutes!
Create your own, reproduce photos
with name affixed. Great anywhere,
from kindergarten to business meet-
' ings, to school sports. Sell for profit!
fF -- Ingenious badge machine makes per.
,+ié.a. r}-' ! manent buttons; kit includes precision
cast hand die press, matching color dies, starter asst. for 25
complete badges including plastic protectors. Sold nationally for
several dollars each, yours will pay off fast. Step-by-step instrs.
Stock No: 71,974 AV $31.50 Ppd.
KNOW YOUR ALPHA FROM THETA!,
For greater relaxation, concentration, listen to
your Alpha -Theta brainwaves. Ultra -sensitive
electrode headband slips on/off in seconds -
eliminates need for messy creams, etc. Atch'd
toamplifier, filters brainwaves, signals beep for
ea. Alpha or Theta wave passed. Monitoring
button stimulates Alpha sound; audio & visual
(L. E.D.) feedback. Reliable, easy -to -use unit comparable to costlier models. Com-
pletely safe. Comprehensive instruction booklet.
No. 1635AV (8x3x4"; 24. oz.)
LOW COST "STARTER" UNIT
No. 71809AV
$134.50 Ppd.
$55.00 Ppd.
ó
GET A CHARGE'
FROM THE SUN!
Our 12V Solar Battery Charger allows
direct conversion of light -to -electricity.
Compact panel put on a boat can
automatically charge its 12V battery
over entire daylight period. Use any-
where for a trickle charge. Big value,
it comprises 30 '/2V silicon solar cells in
series w/diode.
No. 71,971AV (AB, 30 W-HRS./WK.) $89.95 Ppd.
9 x 18" HI CURRENT MODEL (6W, 12V, 500 mA)
No. 72,010AV (AB. 150 W-HRS./WK.) $420.00 Ppd.
6 x 6" LO VOLTAGE MODEL (1.5V, .38W, 250 mA)
No. 42,172AV $49.95 Ppd.
MAIL COUPON FOR
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CATALOG!
164 PAGES MORE THAN J
4500 UNUSUAL
BARGAINS
Completely new Catalog. Packed with huge selection of telesf oyes, mi. I
croscopes, binoculars. magnets, magnifiers. prisms, photo components,
ecology and Unique Lighting items, parts, kits, accessories - many
hardto-get surplus bargains. 100's of charts, illustrations. For hobby.
ists, experimenters, schools. industry.
EDMUND SCIENTIFIC CO.
300 Edscorp Building, Barrington, N.1. 08007
Please rush Free Giant Catalog "AV"
Name
I
Address
State Zip
112
I
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'I
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own channel (max.
controls, controlled
housing; instr.
Stock No. 41,831AV $18.95 Ppd
r1tdrl,
_
ASTRONOMICAL MIRROR KITS
Grind your own mirror for powerful
telescopes. Kit contains fine annealed pyrex
mirror blank, tool, abrasives, diagonal
mirror, and eyepiece lenses. Instru-
ments you build range in value from $75.00
to hundreds pf dollars.
Stock No. 70,003AV ... 41/4" diam. Vs" thick $13.75 Ppd.
Stock No. 70,004AV ... 6" diam. 1" thick $19.75 Ppd.
Stock No. 70,005AV ... 8" diam. 1%" thick $32.75 Ppd.
Stock No. 70,006AV ... 10" diam. 13/4" thick (30 lbs.) $58.00 FOB
Stock No. 70,007AV ... 121/2" diam. 21/4" thick (46 lbs.) $98.50 FOB
3" ASTRONOMICAL
REFLECTING TELESCOPE
See stars, moon, planets close-up!
30 to 90X. Famous Mt. Palomar Type.
Aluminized & overcoated 3" diameter
f/10 primary mirror, ventilated cell. Fork type
equatorial mount. Durable PVC tube. In-
cludes 1" F.L. 30X Ramsden, Barlow
lens to triple power, 3X finder
telescopes, hardwood tripod. FREE: "STAR CHART", "HOW TO USE" book.
Stock No. 85,240AV $49,95 Ppd.
DELUXE 3" REFLECTOR TELESCOPE #80,162ÁV $79.95 Ppd.
41/4" REFLECTOR (45X to 135X) #85,105AV $149.50 FOB
6" REFLECTOR (48X to 360X) #85,187AV $249.50 FOB
COMPLETE" & MALL- WITH "CHECK.` C1R.
EDMUND SCIENTIFIC CO. 300 Edscorp Building, Barrington, N.J. 08007
PLEASE SEND
GIANT FREE
CATALOG "AV"
3 -CHANNEL COLOR ORGAN KIT
Easy to build low-cost kit needs no
technical knowledge. Completed unit
has 3 bands of audio frequencies to mod-
ulate 3 independent strings of colored lamps
(i.e. "lows" -reds, "middles" -greens, "highs" -
blues. Just connect hi-fi, radio, power
lamp etc. & plug ea. tamp string into
300w ea.). Kit features 3 neon indicators, color intensity
individ SCR circuits; isolation transformer; custom plastic
How Many Stock No. Description Price Each Total
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including 29.95 -value walnut veneer case
The Realistic® STA-250 deke-s 44 watts RMS per channel
at 8 ohms (202 watts IHF ±1 dB total). Its THD at half power (1
kHz) is actually less than 0.1%. Obviously the STA-250 keeps
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tuning, two FET's in the front end and two IC's. the FM is
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$22.95 -Value Elliptical Cartridge
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CIRCLE NO. 32 ON READERS SERVICE CARD
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Why you should select your turntable
more carefully than any other component.
Every component is important to the total - you should consider what you'require of operating. °
performance of an audio system, but -the turntable convenience and flexibility. For example, if you don't
is critical. It is the only component that physically
handles your biggest investment in musical
enjoyment:' your record collection.
In time, your changing tastes can outgrow your é two or more records in sequence, you will want a ".
present amplifier and speakers. But regardless turntable with record changing ability. .
of how these components affect the reproduction of ' - All Dual turntables easily fulfill every -
music, they cannot do.anything to harm your records. lfequirement for record playback,and preservation
Not so the turntable: A tonearm that does not andfevery requirement for user convenience.
allow the stylus to track the grooves lightly, k Which is why the readers of the leading
accurately and with perfect
balance can.turn the stylus into a;
destructive instrument easily
capable of lopping off the sharp -
contours which carry the high
frequencies. When that
,, happens, the clean high notes
becomefuzzy memor es.
Permanently. There s lust no
way to restore a damaged
record. Even the
. best equipment
can't replace
notes once
they're gone.
After
considering
what your.
records .
require for
longevity,
1 -:-.
From front to reorl. Duch
r
relish risking your stylus and records by handling the
tonearm each time you playa record, you will want
an automatic turntable. And if you desire to play
audio and music magazines own more
Duals than any other turntable. It's'
also why so many audio professionals
are qiite satisfied with even thé
lowest -priced Dual.
Please write for oúr
very informative 'brochures
and complete repr?nts of ó
i ndépendent -est reports.
The more carefully you
read them, the more
likely you o e to
select a Dual.
Any Dual.ffl
United Audio Products
120 So. Columbus Ave.,
Mt. Vernon, N.Y 10553: -
Exclusive Distribution Agency for Dual .
1259.95; Duo' 1228, 5139.95; Dual 122615154
D
5; Dual 1225, $1.2193'5..°°
E NQ. 4 ON READERS SERVICE CA -R'.' -
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