Littelfuse Sensors Catalog
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PRODUCT
CATALOG &
DESIGN GUIDE
Proximity | Level | Speed | Flow
About This Guide
This guide provides an introduction to magnetic sensing and options for value-added
custom design packages. It also offers practical suggestions for selecting reed switches,
reed sensors and Hall effect sensors for a variety of applications.
Topic Page
Introduction to Magnetic Sensing 2–3
Value-Added Customization 3
Reed Switches 4–5
Hall Effect Sensors 7
Reed Sensors 8–9
Reed Relays 10
Magnetic Actuators 11
Applications 12–15
WHY CHOOSE LITTELFUSE
Littelfuse, Inc. is the global leader in circuit protection solutions. Our
company offers the broadest spectrum of circuit protection technologies
along with products that can be used in any application that requires
electrical energy.
Complementing our vast portfolio of circuit protection products is
a global network of technical support and design expertise. Using
our decades of design experience, we help you address unique
application challenges and achieve regulatory compliance.
Your Single Source
Littelfuse offers the world’s most diverse and extensive circuit protection
product line. If we do not have an off-the-shelf product to meet your needs,
we will work with you to develop a forward-thinking solution that precisely
fits your application. Our goal is to provide the most comprehensive range
of options so that you will not have to make compromises in your designs.
Testing Support
Through our network of Global Labs located in China, Germany,
Japan, Mexico, Philippines and the U.S., we design innovative circuit
protection solutions and provide customer application support and testing.
Our unique capabilities include performance testing, material analysis and
regulatory compliance testing. The dedication of our Global Labs ensures
the outstanding performance, safety and reliability of our products
and support services for our worldwide customer base.
Application Knowledge
At Littelfuse, our expertise involves applying reliable and efficient circuit
protection solutions, innovative technologies and global resources to
address circuit protection challenges in a variety of applications. We utilize
a worldwide network of research teams that focus on product development
and support, design-in programs and application testing in our Global Labs.
Global Support
Littelfuse products, application knowledge and technical support are
available around the globe. We offer a network of regional customer
support offices and hundreds of authorized distributors to assist
you with your circuit protection requirements.
WHY CHOOSE LITTELFUSE SENSORS
Hamlin, now part of Littelfuse, Inc., has a long, rich history of leading
the industry in providing magnetic sensing solutions. Our experts
are committed to delivering the best products and solutions
for your specific needs.
Our global organization provides:
• Custom sensor designs per customer specifications
• Vertically integrated manufacturing
• In-house magnetic simulation support
• Quick turnaround for custom sensor prototypes
Quality Assurance
Our global manufacturing facilities abide by strict quality
assurance requirements and hold the following quality
management system registrations:
1
hamlin.com | littelfuse.com
59135
(High-Temperature Flange Mount
Reed Sensor)
59010
(Ultra-Mini Firecracker)
MDCG-4
(Reed Switch)
59050
(Overmolded Reed Switch)
55140
(Flange Mount
Hall Effect Sensor)
Littelfuse electronics product portfolio includes Hamlin
REED SWITCHES
A reed switch has two ferromagnetic blades (reeds) contained within a tubular glass envelope that
is hermetically sealed at each end. The contacts on each reed blade have a thin layer of precious metal
material deposited on them. There is usually nitrogen gas on the inside of the glass envelope to eliminate
the presence of oxygen and ensure that the contacts will not oxidize. Reed switches are activated
by a permanent magnet or an electromagnet. The reed switch and magnetic field combination
is commonly known as the “magnetic circuit.”
REED SENSORS
Reed sensors are reed switches that are packaged within an external housing for simplified mounting/
connecting and additional protection against environmental influences. These sensors are typically
mounted in mechanical systems. A bare reed switch can easily be mounted on circuit boards. However,
for an application such as a door security sensor, the reed switch needs a protective shell/housing
for handling and mounting. These packages offer resistance to mechanical stress by protecting
the bare glass of the reed switch.
REED RELAYS
A reed relay is made by combining a reed switch with a copper coil. Like other relays, this provides
galvanic isolation between the coil input and the controlled contact(s). However, because of the small size
and magnetic efficiency of the reed switch, the power required to drive the coil is lower than most other
types of relays. Other advantages include high insulation resistance, low contact resistance and long
contact life. Reed relays are used in many applications, including automotive, test equipment, security,
medical and process control equipment.
Comparing Reed vs. Hall Effect
Although there are differences
between reed switch and
Hall effect technologies,
both platforms offer practical
advantages for various
applications. Here is a
comparison of the benefits
of each technology.
2
Reed
Switch
Hall Effect
Sensor
•Noncontact sensing element •
•Zero power consumption
High-Frequency operation •
•Digital switching •
Linear sensing •
Integrated circuitry •
Ultra-small package size •
•Electrical load capability
•EMC/ESD immunity
OPEN
Hold
Close
MAGNET
-X
mm X
mm
X
-X
O
Y
mm
SN
Y
Figure 2-Two-pole linear activation,
parallel orientation
OPEN
Hold
Close
MAGNET
-X
mm X
mm
X
-X
O
Y
mm
S
N
Y
Close
OPEN
Hold
Figure 3-Single-pole linear activation,
perpendicular orientation
Figure 1-Magnetic field lines
must be aligned parallel to a
reed switch’s contacts in order
to open/close the contacts
Introduction to
Magnetic Sensing
The relative stiffness of the
reed blades along with the
small gap and overlap between
the two contacts controls the
sensitivity of the reed switch.
The sensitivity of the switch is
the amount of magnetic field
that is required to actuate the
contact an open or closed
mode. It is measured in
units of ampere-turns (AT).
Most reed switches have a
sensitivity range of 10–30 AT,
where 10 AT is more sensitive
than 30 AT.
SN
S
NS
N
SN
S
N
S
N
SNS
N
S
N
Littelfuse electronics product portfolio includes Hamlin
PACK
3
hamlin.com | littelfuse.com
HALL EFFECT SENSORS
A Hall effect device is a semiconductor-based integrated circuit with Hall plates that respond to
magnetic fields. Additional circuitry is added for power supply and signal conditioning, temperature
compensation and EMC/ESD protection. Hall effect devices provide digital or analog output signals that
are used for proximity and continuous rotary or linear positioning. Unlike a reed switch, a Hall effect
device contains active circuitry, so it draws a small amount of current at all times. Hall effect devices
come in two- or three-wire versions. Some devices are programmable.
MAGNETIC ACTUATORS
Littelfuse offers a wide range of magnetic actuators that are packaged in shapes similar to the relative
mating sensors. We also offer a limited family of bare magnets with various grades of materials,
including ferrite (ceramic), AlNiCo and neodymium iron boron (NdFeB) materials.
Littelfuse specializes in custom design packages that meet our customers’ needs for both reed
and Hall effect sensor designs. Several of our vertically integrated processes are listed below.
Joining/Sealing Methods
• Ultrasonic welding
• Heat staking
Encapsulation
• Transfer overmold
• Low-pressure overmold
• Epoxy/urethane
• Meter/mix dispensing
Terminations
• Injection molding
• Insert molding
• Automatic cut, strip
and crimp
• Littelfuse applies many
customer-specified
connectors
Circuit Board Assembly
• Vision systems
• In-circuit test
• Pick and place
• Reow
• Wave
• Robotic
Reed Switch and Hall Effect
• Automatic switch assembly machines
• Custom reed switch forming equipment
• Automated testing
• Automatic cut and form
• Tape & reel packaging for SMD and other
custom design requirements
Assembly Methods
• Automated
• Cellular
• Manual
100% End of Line Testing
• Hermetic seal test
• Magnetic actuation
• Contact resistance
Value-Added Customization
Custom Magnet Solutions
• Magnetic simulation and modeling
for customer-specific designs
• Integral magnets within the sensor
• Magnetic circuits with tight
tolerances available
Notes:
For details on electrical specifications, visit hamlin.com
A:SPST-NO - Single Pole Single Throw - Normally Open
C:SPDT-CO - Single Pole Double Throw - Changeover
4
Power Size Terminals Switch Type Package P/N
Body Length
(mm)/[Inch]
Total Length
(mm)/[Inch]
Low Power
Small
Leads
A: SPST-NO Glass MITI-7 7.0 0 [. 276 ] 40.38 [1.590]
A: SPST-NO Glass MDSR-10 10.16 [.400] 40.38 [1.590]
A: SPST-NO Glass MDSR-7 12.70 [.500] 40.38 [1.590]
SMD
A: SPST-NO Glass MISM-7 7.00 [. 276] 13.72 [.540]
A: SPST-NO Glass MDSM-10 10.16 [.400] 15.62 [.615]
Medium
Leads
A: SPST-NO Glass FLEX-14 14.0 0 [.551] 44.30 [1.744]
A: SPST-NO Glass MDCG-4 15.24 [.600] 40.38 [1.590]
A: SPST-NO Glass MACD-14 14.00 [.551] 44.30 [1.744]
C: SPDT-CO Glass MDRR-DT 14.73 [.580] 51.66 [2.034]
SMD
A: SPST-NO Glass MDSM-4 15.24 [.600] 19.30 [.760]
A: SPST-NO Glass MASM -14 14.00 [.551] 44.30 [1.744]
C: SPDT-CO Glass MDSM-DT 14.73 [.580] 25.40 [1.00]
Both Leads
and SMD
A: SPST-NO Overmolded 59165 16.00 [.630] 20.20 [.795]
A: SPST-NO Overmolded 59166 16.00 [.630] 19.51 [.768]
A: SPST-NO Overmolded 59170 11.43 [.450] 16.25 [.640]
Leads
A: SPST-NO Overmolded 59045 -1 17.78 [.700] 15.24 [.600]
A: SPST-NO Overmolded 59050 -1 22.86 [.900] 20.32 [.800]
High Power
Medium
Leads
A: SPST-NO Glass HA15 -2 15.24 [.600] 40.38 [1.590]
A: SPST-NO Glass MLRR-4 15.24 [.600] 40.38 [1.590]
A: SPST-NO Glass MLRR-3 15.24 [.600] 56.64 [2.230]
A: SPST-NO Glass MARR-5 19.69 [.775] 56.77 [2.235]
SMD
A: SPST-NO Glass MLSM-4 15.24 [.600] 19.56 [.770]
A: SPST-NO Glass MLSM-3 15.24 [.600] 19.56 [.770]
Leads A: SPST-NO Overmolded 59050-2 22.86 [.900] 20.32 [.800]
Leads
A: SPST-NO Glass MRPR-3 19.69 [.775] 56.64 [2.230]
A: SPST-NO Glass MRPR-8 20.32 [.800] 56.64 [2.230]
Large
A: SPST-NO Glass DRR-129 50.80 [2.000] 82.55 [3.250]
C: SPDT-CO Glass DRR-DTH 39.67 [1.562] 85.73 [3.375]
C: SPDT-CO Glass DRT-DTH 39.67 [1.562] 85.73 [3.375]
MACD-14
MITI-7
MDSM-4
DRR-DTH
Reed Switches
Littelfuse electronics product portfolio includes Hamlin
Lead Modifications
Littelfuse can cut and/or form the reed switch leads to meet your dimensional
requirements. Most lead modifications can be done by Littelfuse without
any additional tooling costs. 5
hamlin.com | littelfuse.com
Power Size Terminals Switch Type Package P/N
Body Length
(mm)/[Inch]
Total Length
(mm)/[Inch]
Low Power
Small
Leads
A: SPST-NO Glass MITI-7 7.0 0 [. 276 ] 40.38 [1.590]
A: SPST-NO Glass MDSR-10 10.16 [.400] 40.38 [1.590]
A: SPST-NO Glass MDSR-7 12.70 [.500] 40.38 [1.590]
SMD
A: SPST-NO Glass MISM-7 7.00 [. 276] 13.72 [.540]
A: SPST-NO Glass MDSM-10 10.16 [.400] 15.62 [.615]
Medium
Leads
A: SPST-NO Glass FLEX-14 14.0 0 [.551] 44.30 [1.744]
A: SPST-NO Glass MDCG-4 15.24 [.600] 40.38 [1.590]
A: SPST-NO Glass MACD-14 14.00 [.551] 44.30 [1.744]
C: SPDT-CO Glass MDRR-DT 14.73 [.580] 51.66 [2.034]
SMD
A: SPST-NO Glass MDSM-4 15.24 [.600] 19.30 [.760]
A: SPST-NO Glass MASM -14 14.00 [.551] 44.30 [1.744]
C: SPDT-CO Glass MDSM-DT 14.73 [.580] 25.40 [1.00]
Both Leads
and SMD
A: SPST-NO Overmolded 59165 16.00 [.630] 20.20 [.795]
A: SPST-NO Overmolded 59166 16.00 [.630] 19.51 [.768]
A: SPST-NO Overmolded 59170 11.43 [.450] 16.25 [.640]
Leads
A: SPST-NO Overmolded 59045 -1 17.78 [.700] 15.24 [.600]
A: SPST-NO Overmolded 59050 -1 22.86 [.900] 20.32 [.800]
High Power
Medium
Leads
A: SPST-NO Glass HA15 -2 15.24 [.600] 40.38 [1.590]
A: SPST-NO Glass MLRR-4 15.24 [.600] 40.38 [1.590]
A: SPST-NO Glass MLRR-3 15.24 [.600] 56.64 [2.230]
A: SPST-NO Glass MARR-5 19.69 [.775] 56.77 [2.235]
SMD
A: SPST-NO Glass MLSM-4 15.24 [.600] 19.56 [.770]
A: SPST-NO Glass MLSM-3 15.24 [.600] 19.56 [.770]
Leads A: SPST-NO Overmolded 59050-2 22.86 [.900] 20.32 [.800]
Leads
A: SPST-NO Glass MRPR-3 19.69 [.775] 56.64 [2.230]
A: SPST-NO Glass MRPR-8 20.32 [.800] 56.64 [2.230]
Large
A: SPST-NO Glass DRR-129 50.80 [2.000] 82.55 [3.250]
C: SPDT-CO Glass DRR-DTH 39.67 [1.562] 85.73 [3.375]
C: SPDT-CO Glass DRT-DTH 39.67 [1.562] 85.73 [3.375]
Switching
Power (W)
Switching
Voltage (V)
Switching
Current (A)
Contact
Resistance (Ω)
Operating
Temperature (°C)
Magnetic
Sensitivity (AT) Certification
RoHS
Compliance
10 170 Vdc, 120 Vac 0.25 Adc, 0.18 Aac 0.15 -40 to +125 6-20 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.12 -40 to +125 10 -25 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.1 -40 to +125 10-25 RoHS
10 170 Vdc, 120 Vac 0.25 Adc, 0.18 Aac 0.15 -40 to +125 6-20 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.12 -40 to +125 10 -25 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.1 -40 to +125 10-30 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.1 -40 to +125 12-38 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.1 -40 to +125 10-30 RoHS
5175 Vdc, 120 Vac 0.25 Adc, 0.18 Aac 0.1 -40 to +125 15-30 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.1 -40 to +125 12-38 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.1 -40 to +125 10-30 RoHS
5175 Vdc, 120 Vac 0.25 Adc, 0.18 Aac 0.1 -40 to +125 15-30 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.1 -40 to +125 10-25 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.1 -40 to +125 10-26 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.15 -40 to +125 10 -25 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.2 -40 to +105 15-30 RoHS
10 200 Vdc, 140 Vac 0.5 Adc, 0.35 Aac 0.2 -40 to +105 12-33 RoHS
20 200 Vdc, 265 Vac 0.5 Adc, 0.35 Aac 0.1 -20 to +125 17-38 RoHS
20 200 Vdc, 140 Vac 1.0 Adc, 0.7 Aac 0.1 -40 to +125 17-38 RoHS
20 200 Vdc, 140 Vac 1.0 Adc, 0.7 Aac 0.1 -40 to +125 17-38 RoHS
10 1000 Vdc, 700 Vac 0.5 Adc, 0.35 Aac 0.1 -75 to +125 17-38 RoHS
20 200 Vdc, 140 Vac 1.0 Adc, 0.7 Aac 0.1 -40 to +125 17-38 RoHS
20 200 Vdc, 140 Vac 1.0 Adc, 0.7 Aac 0.1 -40 to +125 17-38 RoHS
20 200 Vdc, 265 Vac 0.5 Adc, 0.35 Aac 0.2 -20 to +105 17-33 RoHS
50 200 Vdc, 140 Vac 1.5 Adc, 1.1 Aac 0.1 -40 to +125 22-43 RoHS
50 250 Vdc, 265 Vac 1.0 Adc, 0.7 Aac 0.1 -20 to +125 22-43 RoHS
100 400 Vdc, 280 Vac 3.0 Adc, 2.1 Aac 0.1 -40 to +125 42-83 RoHS
30 500 Vdc, 350 Vac 0.5 Adc, 0.35 Aac 0.125 -20 to +125 50-80 RoHS
50 500 Vdc, 350 Vac 1.5 Adc, 1.0 Aac 0.5 -20 to +125 50-80 RoHS
MDSM-DT
59165
59045
MRPR-3
Our reed switch, Hall effect sensor and reed sensor products are ideally suited for
various sensing applications, including proximity, level, speed and flow, as shown
in the table. Customizations, including various connectors and wire lengths,
are available for all our standard products. For product specifications
and available options, refer to the individual product datasheets.
Sensor Type Application
Proximity Level Speed Flow
Reed Switches • • • •
Hall Effect Sensors
Flat Pack • • •
Round Flange Mount •
Flat Flange Mount • • •
Threaded Barrel •
Vane • •
Rotary/Angular •
Reed Sensors
Firecracker • • • •
Threaded Barrel • • •
Flange/Flat Pack • • •
Float •
Vane • •
Lever Arm •
Seat Occupancy •
6
Sensors,
Reed Relays
and Magnetic
Actuators
Littelfuse electronics product portfolio includes Hamlin
FLaT PaCK
This sensor’s rectangular package is ideally suited for mounting on a flat surface.
It is designed for use in a wide range of environments.
ROUNd FLaNgE MOUNT
Its cylindrical package has a flat flange to accommodate mounting on a flat surface.
This sensor is ideally suited for sensing a rotating ferrous metal target.
FLaT FLaNgE MOUNT
The low-profile, rectangular package is designed for installation in small-gap spaces.
Product
Series Description
Overall Dimensions Operating
Supply
Voltage
Operating
Supply
Current Output
Type
Output
High
Output
Low
Temperature Rating
mm (inch) mA ˚C
L x W x H Vdc Max. Max. Operating Storage
55140
Flange Mount Hall, 2-Wire 23.00 (0.906) x 14.00 (0.551) x 6.00 (0.236) 3.75 to 24 N/A Current N/A 2.2 - 5.6 mA -40 to +100 -65 to +105
Flange Mount Hall, 3-Wire 23.00 (0.906) x 14.00 (0.551) x 6.00 (0.236) 3.8 to 24 N/A Voltage Sinking/Open
Collector 0.4 V @ 20 mA -40 to +100 -65 to +105
Flange Mount Hall, Analog 23.00 (0.906) x 14.00 (0.551) x 6.00 (0.236) 4.5 to 5.5 N/A Analog Voltage 4.65 V 0.35 V -40 to +100 -65 to +105
55300 Flat Pack Rotary Hall 28.50 (1.122) x 20.40 (0.803) x 6.35 (0.250) 4.5 to 5.5 16 Analog Voltage
or PWM 4.5 V 0.5 V -40 to +105 -65 to +105
55310 Flat Pack Digital Hall 28.50 (1.122) x 20.40 (0.803) x 6.35 (0.250) 4.75 to 24 6 Current N/A 20 mA -40 to +105 -65 to +105
55320 Flat Pack Linear Hall 28.50 (1.122) x 20.40 (0.803) x 6.35 (0.250) 4.5 to 5.5 16 Analog Voltage
or PWM N/A -8 to +8 mA
0.5 to 4.5 V -40 to +105 -65 to +125
Product
Series Description
Overall Dimensions Operating
Supply
Voltage
Operating
Supply
Current Output
Type
Output
High
Output
Low
Temperature Rating
mm (inch) ˚C
L x W x H Vdc mA Max. Operating Storage
55505 Flange Mount Geartooth Hall 17.86 (0.703) x 36.75 (1.447) x 41.40
(0.551) 4.75 to 24 N/A Digital Vdd-2 0.6 V @ 20
mA -40 to +125 -65 to +125
Product
Series Description
Overall Dimensions Operating
Supply
Voltage
Operating
Supply
Current Output
Type
Output
High
Output
Low
Temperature Rating
mm (inch) ˚C
L x W x H Vdc mA Max. Operating Storage
55100
Miniature Flange Mount Hall, 2-Wire 25.50 (1.004) x 11.00 (0.433) x 3.00 (0.118) 3.75 to 24 N/A Current N/A N/A -40 to +100 -65 to +105
Miniature Flange Mount Hall, 3-Wire 25.50 (1.004) x 11.00 (0.433) x 3.00 (0.118) 3.8 to 24 N/A Voltage Sinking/Open
Collector 0.4 V @ 10 mA -40 to +100 -65 to +105
Miniature Flange Mount Hall, Analog 25.50 (1.004) x 11.00 (0.433) x 3.00 (0.118) 4.5 to 5.5 N/A Analog Voltage 4.65 V 0.35 V -40 to +100 -65 to +105
55110 LED Flange Mount Hall 34.00 (1.399) x 14.00 (0.551) x 10.00 (0.394) 3.8 to 24 N/A Voltage Vdd-2 @ 0.1 mA 0.4 V @ 20 mA -40 to +85 -65 to +85
Hall Effect Sensors
Product
Series Description
Overall Dimensions Operating
Supply
Voltage
Operating
Supply
Current Out put
Type
Output
High
Output
Low
Temperature Rating
mm (inch) ˚C
L x W x H Vdc mA Max. Operating Storage
55085 Miniature Vane, PCB Mount, Hall 28.00 (1.102) x 13.50 (0.531) x 9.00 (0.354) 3.8 to 24 N/A Voltage Sinking/Open
Collector 0.4 V @ 20 mA -40 to +100 -65 to +105
Product
Series Description
Overall Dimensions Operating
Supply
Voltage
Operating
Supply
Current Output
Type
Output
High
Output
Low
Temperature Rating
mm (inch) ˚C
Thread Pitch x L Vdc mA Max. Operating Storage
55075 Stainless Steel M12 Geartooth Hall M12 x 1 Pitch x 46.00 (1.811) 4.75 to 25.2 N/A Digital Vdd - 2 0.6 V @ 20 mA -40 to +85 -65 to +85
Product
Series Description
Overall Dimensions Operating
Supply
Voltage
Operating
Supply
Current Output
Type
Output
High
Output
Low
Temperature Rating
mm (inch) ˚C
L x W x H Vdc mA Max. Operating Storage
55250 Rotary Hall 50.00 (1.968) x 37.30 (1.469) x 28.25 (1.112) 4.5 to 5.5 16 Analog Voltage
or PWM 4.5 V 0.5 V -40 to +125 -65 to +125
VaNE
This sensor is packaged with a magnet and a Hall effect sensing element.
It is typically used in applications with a moving ferrous metal part.
THREadEd BaRREL
Designed for harsh environments, this sensor may easily be mounted and adjusted
using the supplied retaining nuts. Its cylindrical package is available with metric threads.
ROTaRY/aNgULaR
This sensor is packaged with a magnet and a Hall effect sensing element.
It provides instantaneous angular position measurement.
7
hamlin.com | littelfuse.com
8
Product
Series Description
Overall Dimensions Contact
Rating
Switching
Voltage
Breakdown
Voltage
Switching
Current
Contact
Resistance, Initial Mating
Actuator
mm (inch) W Vdc Vdc A Ohms
Ø x L Max. Max. Min. Max. Max.
59010 Ultra-Mini Firecracker 3.13 (0.123) x 9.00 (0.354) 10 170 175 0.25 0.25 57020
59020 Mini Firecracker 5.10 (0.201) x 15.24 (0.600) 10 170 175 0.25 0.25 57020
59021 Aluminum Mini Firecracker 5.10 (0.201) x 15.24 (0.600) 10 170 175 0.25 0.25 57020
59025
Firecracker, Normally Open 6.22 (0.245) x 25.40 (1.000) 10 200 250 0.5 0.2
57025
Firecracker, Normally Open High Voltage 6.22 (0.245) x 25.40 (1.000) 10 300 450 0.5 0.2
Firecracker, Changeover 6.22 (0.245) x 25.40 (1.000) 5 175 200 0.25 0.2
Firecracker, Normally Closed 6.22 (0.245) x 25.40 (1.000) 5 175 200 0.25 0.2
59030
Firecracker, Normally Open 6.22 (0.245) x 38.10 (1.500) 10 200 250 0.5 0.2
57030
Firecracker, Normally Open High Voltage 6.22 (0.245) x 38.10 (1.500) 10 300 450 0.5 0.2
Firecracker, Changeover 6.22 (0.245) x 38.10 (1.500) 5 175 200 0.25 0.2
Firecracker, Normally Closed 6.22 (0.245) x 38.10 (1.500) 5 175 200 0.25 0.2
FIRECRACKER
This sensor offers a slim, cylindrical package that is suitable for mounting on a frame.
Reed Sensors
Sensors, Reed Relays and Magnetic Actuators (continued)
Product
Series Description
Overall Dimensions Contact
Rating
Switching
Voltage
Breakdown
Voltage
Switching
Current
Contact
Resistance, Initial
mm (inch) W Vdc Vdc A Ohms
Ø x L Max. Max. Min. Max. Max.
59630
Float Sensor, Normally Open 23.70 (0.930) x 43.70 (1.720) 10 200 250 0.5 0.2
Float Sensor, Normally Open High Voltage 23.70 (0.930) x 43.70 (1.720) 10 300 450 0.5 0.2
Float Sensor, Changeover 23.70 (0.930) x 43.70 (1.720) 5 175 200 0.25 0.2
Float Sensor, Normally Closed 23.70 (0.930) x 43.70 (1.720) 5 175 200 0.25 0.2
59300 Level Sensor, Normally Open (Float Not Included) 19.90 (0.783) x 67.55 (2.660) 10 200 250 0.5 0.2
Product
Series Description
Overall Dimensions Contact
Rating
Switching
Voltage
Breakdown
Voltage
Switching
Current
Contact
Resistance, Initial
mm (inch) W Vdc Vdc A Ohms
L x W x H Max. Max. Min. Max. Max.
59085
Vane Sensor, Normally Open 25.40 (1.000) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
Vane Sensor, Changeover 25.40 (1.000) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
Vane Sensor, Normally Closed 25.40 (1.000) x 19.05 (0.750) x 6.35 (0.250) 10 200 250 0.5 0.2
Vane Sensor, Normally Closed High Voltage 25.40 (1.000) x 19.05 (0.750) x 6.35 (0.250) 10 300 450 0.5 0.2
59090
Heavy Duty Vane Sensor, Normally Closed 32.50 (1.280) x 32.25 (1.271) x 23.25 (0.915) 10 200 250 0.5 0.2
Heavy Duty Vane Sensor, Normally Closed High Voltage 32.50 (1.280) x 32.25 (1.271) x 23.25 (0.915) 10 300 450 0.5 0.2
Heavy Duty Vane Sensor, Changeover 32.50 (1.280) x 32.25 (1.271) x 23.25 (0.915) 5 175 200 0.25 0.2
Product
Series Description
Overall Dimensions Contact
Rating
Switching
Voltage
Breakdown
Voltage
Switching
Current
Contact
Resistance, Initial
mm (inch) W Vdc Vdc A Ohms
L x W x H Max. Max. Min. Max. Max.
59250 Push-button Seat Sensor (Reed) 32.51 (1.280) x 26.67 (1.050) x 37.34 (1.470) 10 200 250 0.5 0.2
59251 Seat Sensor with Dome (Reed) 108.20 (4.260) x 69.85 (2.750) x 39.88 (1.570) 10 200 250 0.5 0.2
FLOAT
Designed for liquid-level sensing applications, this sensor has an integral float
magnet and a reed switch.
VANE
Packaged with a magnet and a reed switch, this sensor is typically used in applications
with a moving ferrous metal part.
SEAT OCCUPANCY
Packaged with an integral magnet and a reed switch, this sensor is available in
a push-button configuration or a dome configuration for weight/load distribution.
Littelfuse electronics product portfolio includes Hamlin
9
Product
Series Description
Overall Dimensions Contact
Rating
Switching
Voltage
Breakdown
Voltage
Switching
Current
Contact
Resistance, Initial Mating
Actuator
mm (inch) W Vdc Vdc A Ohms
Thread Pitch x L Max. Max. Min. Max. Max.
59060
Stainless Steel Threaded Barrel Sensor, Normally Open M8 x 1.25 Pitch x 36.00 (1.420) 10 200 250 0.5 0.2
57060
Stainless Steel Threaded Barrel Sensor, Normally Open High Voltage M8 x 1.25 Pitch x 36.00 (1.420) 10 300 450 0.5 0.2
Stainless Steel Threaded Barrel Sensor, Changeover M8 x 1.25 Pitch x 36.00 (1.420) 5 175 200 0.25 0.2
Stainless Steel Threaded Barrel Sensor, Normally Closed M8 x 1.25 Pitch x 36.00 (1.420) 5 175 200 0.25 0.2
59065
Threaded Barrel Sensor (Standard), Normally Open (5/16 x 24) Pitch x 38.10 (1.500) 10 200 250 0.5 0.2
57065
Threaded Barrel Sensor (Standard), Normally Open High Voltage (5/16 x 24) Pitch x 38.10 (1.500) 10 300 450 0.5 0.2
Threaded Barrel Sensor (Standard), Changeover (5/16 x 24) Pitch x 38.10 (1.500) 5 175 200 0.25 0.2
Threaded Barrel Sensor (Standard), Normally Closed (5/16 x 24) Pitch x 38.10 (1.500) 5 175 200 0.25 0.2
59070
Threaded Barrel Sensor (Metric), Normally Open M8 x 1.25mm Pitch x 38.10 (1.500) 10 200 250 0.5 0.2
57070
Threaded Barrel Sensor (Metric), Normally Open High Voltage M8 x 1.25mm Pitch x 38.10 (1.500) 10 300 450 0.5 0.2
Threaded Barrel Sensor (Metric), Changeover M8 x 1.25mm Pitch x 38.10 (1.500) 5 175 200 0.25 0.2
Threaded Barrel Sensor (Metric), Normally Closed M8 x 1.25mm Pitch x 38.10 (1.500) 5 175 200 0.25 0.2
59075
Heavy Duty Threaded Barrel, Normally Open M12 x 1mm Pitch x 46.00 (1.810) 10 200 250 0.5 0.2
57075
Heavy Duty Threaded Barrel, Normally Open High Voltage M12 x 1mm Pitch x 46.00 (1.810) 10 300 450 0.5 0.2
Heavy Duty Threaded Barrel, Changeover M12 x 1mm Pitch x 46.00 (1.810) 5 175 200 0.25 0.2
Heavy Duty Threaded Barrel, Normally Closed M12 x 1mm Pitch x 46.00 (1.810) 5 175 200 0.25 0.2
Product
Series Description
Overall Dimensions Contact
Rating
Switching
Voltage
Breakdown
Voltage
Switching
Current
Contact
Resistance, Initial Mating
Actuator
mm (inch) W Vdc Vdc A Ohms
L X W X H Max. Max. Min. Max. Max.
59105
Terminal Flange Mount Sensor, Normally Open 40.17 (1.582) x 19.05 (0.750) x 6.60 (0.260) 10 200 250 0.5 0.2
57105Terminal Flange Mount Sensor, Normally Open High Voltage 40.17 (1.582) x 19.05 (0.750) x 6.60 (0.260) 10 300 450 0.5 0.2
Terminal Flange Mount Sensor, Normally Closed 40.17 (1.582) x 19.05 (0.750) x 6.60 (0.260) 5 175 200 0.25 0.2
59125
Pinned Flange Mount Sensor, Normally Open 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 10 200 250 0.5 0.2
57125Pinned Flange Mount Sensor, Normally Open High Voltage 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 10 300 450 0.5 0.2
Pinned Flange Mount Sensor, Normally Closed 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
59135
High-Temp Flange Mount Sensor, Normally Open 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 10 200 250 0.5 0.2
57135
High-Temp Flange Mount Sensor, Normally Open High Voltage 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 10 300 450 0.5 0.2
High-Temp Flange Mount Sensor, Changeover 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
High-Temp Flange Mount Sensor, Normally Closed 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
59140
Mini Flange Mount Sensor, Normally Open 23.0 (0.906) x 14.00 (0.551) x 6.00 (0.236) 10 200 250 0.5 0.2
57140
Mini Flange Mount Sensor, Normally Open High Voltage 23.0 (0.906) x 14.00 (0.551) x 6.00 (0.236) 10 300 450 0.5 0.2
Mini Flange Mount Sensor, Changeover 23.0 (0.906) x 14.00 (0.551) x 6.00 (0.236) 5 175 200 0.25 0.2
Mini Flange Mount Sensor, Normally Closed 23.0 (0.906) x 14.00 (0.551) x 6.00 (0.236) 5 175 200 0.25 0.2
59141
Mini Flange Mount Sensor, Normally Open 23.0 (0.906) x 14.00 (0.551) x 6.00 (0.236) 10 200 250 0.5 0.2
57140
Mini Flange Mount Sensor, Normally Open High Voltage 23.0 (0.906) x 14.00 (0.551) x 6.00 (0.236) 10 300 450 0.5 0.2
Mini Flange Mount Sensor, Changeover 23.0 (0.906) x 14.00 (0.551) x 6.00 (0.236) 5 175 200 0.25 0.2
Mini Flange Mount Sensor, Normally Closed 23.0 (0.906) x 14.00 (0.551) x 6.00 (0.236) 5 175 200 0.25 0.2
59145
Flange Mount Sensor, Normally Open 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 10 200 250 0.5 0.2
57145
Flange Mount Sensor, Normally Open High Voltage 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 10 300 450 0.5 0.2
Flange Mount Sensor, Changeover 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
Flange Mount Sensor, Normally Closed 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
59150
Flange Mount Sensor, Normally Open 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 10 200 250 0.5 0.2
57150
Flange Mount Sensor, Normally Open High Voltage 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 10 300 450 0.5 0.2
Flange Mount Sensor, Changeover 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
Flange Mount Sensor, Normally Closed 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) 5 175 200 0.25 0.2
THREadEd BaRREL
Designed with a cylindrical package, this sensor is available with English and metric threads.
It may easily be mounted and adjusted using the supplied retaining nuts.
FLaNgE/FLaT PaCK
This sensor offers a rectangular package that is designed for mounting on a flat surface.
It is suitable for use in a wide range of environments, including high-temperature applications.
Product
Series Description
Overall Dimensions Contact
Rating
Switching
Voltage
Breakdown
Voltage
Switching
Current
Contact
Resistance, Initial
mm (inch) W Vdc Vdc A Ohms
L x W x H Max. Max. Min. Max. Max.
59210 Lever Arm Sensor 24 (0.945) x 23 (0.906) x 10 (0.394) 10 200 250 0.5 0.2
LEVER aRM
This clip frame sensor with a lever arm is ideally suited for paper-path sensing
and security system applications.
hamlin.com | littelfuse.com
10
Product
Series Description
Overall Dimensions Coil Voltage Coil
Resistance Contact Ratings, Switching Contact
Form
Transfer Molded Body External Shield Body
mm (inch) mm (inch) Vdc Vdc Ohms Vdc A W
L x W x H L x W x H Nominal Max. Nominal Max. Max. Max.
HE721A0500
Reed Relay, DIL, SPST-NO 39.50 (0.768) x 7.22 (0.284) x 5.50 (0.217) 20.14 (0.793) x 7.62 (0.300) x 5.82 (0.229)
5 12 500
200 0.5 10 Form AHE721A1200 12 31 1000
HE721A2400 24 46 2150
HE721B0500
Reed Relay, DIL, SPST-NC 39.50 (0.768) x 7.22 (0.284) x 5.50 (0.217) 20.14 (0.793) x 7.62 (0.300) x 5.82 (0.229)
5 6.5 500
200 0.5 10 Form BHE721B1200 12 14 1000
HE721B2400 24 28 2150
HE721C0500
Reed Relay, DIL, SPDT-CO 39.50 (0.768) x 7.22 (0.284) x 5.50 (0.217) 20.14 (0.793) x 7.62 (0.300) x 5.82 (0.229)
5 14 200
175 0.25 5 Form CHE721C1200 12 22 500
HE721C2400 24 44 2000
HE721E0500
Reed Relay, DIL, SPDT-CO 39.50 (0.768) x 7.22 (0.284) x 5.50 (0.217) 20.14 (0.793) x 7.62 (0.300) x 5.82 (0.229)
5 14 200
175 0.25 5 Form CHE721E1200 12 22 500
HE721E2400 24 44 2000
HE721R0500
Reed Relay, DIL, SPDT-CO 39.50 (0.768) x 7.22 (0.284) x 5.50 (0.217) 20.14 (0.793) x 7.62 (0.300) x 5.82 (0.229)
5 14 200
175 0.25 5 Form CHE721R1200 12 22 500
HE721R2400 24 44 2000
HE722A0500
Reed Relay, DIL, DPST-NO 39.50 (0.768) x 7.22 (0.284) x 5.50 (0.217) 20.14 (0.793) x 7.62 (0.300) x 5.82 (0.229)
5 12 200
200 0.5 10 Form AHE722A1200 12 22 500
HE722A2400 24 46 2000
HE751A0500
Reed Relay, DIL, SPST-NO,
High Voltage 39.50 (0.768) x 7.22 (0.284) x 5.50 (0.217) 20.14 (0.793) x 7.62 (0.300) x 5.82 (0.229)
5 12 500
300 0.5 10 Form AHE751A1200 12 21 1000
HE751A2400 24 46 2150
Product
Series Description
Overall Dimensions Coil Voltage Coil
Resistance Contact Ratings, Switching Contact
Form
Transfer Molded Body External Shield Body
mm (inch) mm (inch) Vdc Vdc Ohms Vdc A W
L x W x H L x W x H Nominal Max. Nominal Max. Max. Max.
HE3321A0400
Reed Relay, SIL, SPST-NO 24.13 (0.950) x 7.00 (0.276) x 7.40 (0.291) 24.90 (0.980) x 7.60 (0.299) x 7.80 (0.307)
5 22 500
200 0.5 10 Form AHE3321A1200 12 22 500
HE3321A2400 24 44 2000
HE3321C0500
Reed Relay, SIL, SPDT-CO 24.13 (0.950) x 7.00 (0.276) x 7.40 (0.291) 24.90 (0.980) x 7.60 (0.299) x 7.80 (0.307)
5 11 125
175 0.25 5 Form CHE3321C1200 12 22 500
HE3321C2400 24 44 2000
HE3351A0500
Reed Relay, SIL, SPST-NO,
High Voltage 24.13 (0.950) x 7.00 (0.276) x 7.40 (0.291) 24.90 (0.980) x 7.60 (0.299) x 7.80 (0.307)
5 14 125
300 0.5 10 Form AHE3351A1200 12 22 500
HE3351A2400 24 44 2000
Product
Series Description
Overall Dimensions Coil Voltage Coil
Resistance Contact Ratings, Switching Contact
Form
Transfer Molded Body External Shield Body
mm (inch) mm (inch) Vdc Vdc Ohms Vdc A W
L x W x H L x W x H Nominal Max. Nominal Max. Max. Max.
HE3621A0500
Reed Relay, SIL, SPST-NO 19.05 (0.750) x 5.08 (0.200) x 7.45 (0.293) 19.70 (0.776) x 5.65 (0.222) x 7.87 (0.310)
5 14 500
200 0.5 10 Form AHE3621A1200 12 22 1000
HE3621A2400 24 31 2150
HE3671A0500
Reed Relay, SIL, SPST-NO,
Data Switching 19.05 (0.750) x 5.08 (0.200) x 7.45 (0.293) 19.70 (0.776) x 5.65 (0.222) x 7.87 (0.310)
5 14 500
200 0.5 10 Form AHE3671A1200 12 22 1000
HE3671A2400 24 31 2150
dUaL-IN-LINE (dIL)
Reed relay products are available in standard dual-in-line packages for mounting
on a printed circuit board or socket.
SINgLE-IN-LINE (SIL)
Reed relay products are available in standard single-in-line packages for mounting
on a printed circuit board or socket.
MINIaTURE SINgLE-IN-LINE (SIL)
Reed relay products are available in smaller profile single-in-line packages
for mounting on a printed circuit board or socket.
Reed Relays
Sensors, Reed Relays and Magnetic Actuators (continued)
Littelfuse electronics product portfolio includes Hamlin
11hamlin.com | littelfuse.com
Product
Series Description
Overall Dimensions
Material
Recommended Operating Temp.
mm (inch) ˚C
L x W x H Max.
H-31 AlNiCo Magnet 12.70 (0.500) x 1.60 (0.062) x 1.60 (0.062) AlNiCo-5 300
H-32 AlNiCo Magnet 25.40 (1.000) x 4.80 (0.190) x 4.80 (0.190) AlNiCo-5 300
H-33 AlNiCo Magnet 19.10 (0.750) x 3.20 (0.120) x 3.20 (0.120) AlNiCo-5 300
H-34 AlNiCo Magnet 25.40 (1.000) x 6.35 (0.250) x 6.35 (0.250) AlNiCo-5 300
H-40 Neodymium Magnet 7.62 (0.300) x 3.18 (0.125) x 3.18 (0.125) NdFeB 45H 120
H-41 Neodymium Magnet 19.05 (0.750) x 3.18 (0.125) x 3.18 (0.125) NdFeB 35H 120
H-58 Neodymium Magnet 21.00 (0.827) x 7.00 (0.276) x 4.70 (0.185) NdFeB 35H 120
57105 Actuator for Terminal Flange Mount Sensor 40.17 (1.582) x 19.05 (0.750) x 6.35 (0.250) AlNiCo-5 105
57125 Actuator for Pinned Flange Mount Sensor 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) AlNiCo-5 300
57135 Actuator for High-Temp Flange Mount Sensor 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) AlNiCo-5 150
57140 Actuator for Mini Flange Mount Sensor 23.00 (0.906) x 14.00 (0.551) x 6.00 (0.236) AlNiCo-5 105
57141 Actuator for Mini Flange Mount Sensor 23.00 (0.906) x 14.00 (0.551) x 6.00 (0.236) NdFeB 35H 105
57145 Actuator for Flange Mount Sensor 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) AlNiCo-5 105
57150 Actuator for Flange Mount Sensor 28.57 (1.125) x 19.05 (0.750) x 6.35 (0.250) AlNiCo-5 105
57045 Actuator for Mini PCB Mount Overmolded 17.78 (0.700) x 3.30 (0.130) x 4.32 (0.170) AlNiCo-5 105
57050 Actuator for PCB Mount Overmolded 22.86 (0.900) x 4.57 (0.180) x 4.57 (0.180) AlNiCo-5 105
Product
Series Description
Overall Dimensions
Material
Recommended Operating Temp.
mm (inch) ˚C
Ø x L Max.
H-35 Neodymium Magnet 6.35 (0.250) x 6.35 (0.250) NdFeB 35H 120
H-48 Neodymium Magnet 4.40 (0.173) x 6.00 (0.236) NdFeB 35SH 120
CM-1 Ceramic Magnet 12.70 (0.500) x 5.08 (0.200) Ceramic-5 125
H-36 AlNiCo Magnet 4.60 (0.182) x 25.40 (1.000) AlNiCo-5 300
H-315 AlNiCo Magnet 3.00 (0.118) x 15.00 (0.590) AlNiCo-5 300
H-420 AlNiCo Magnet 4.00 (0.157) x 20.0 (0.787) AlNiCo-5 300
H-625 AlNiCo Magnet 6.00 (0.236) x 25.0 (0.984) AlNiCo-5 300
57020 Actuator for Mini Firecracker 5.10 (0.201) x 15.24 (0.600) AlNiCo-5 105
57022 Actuator for Firecracker 5.80 (0.228) x 25.40 (1.000) AlNiCo-5 105
57025 Actuator for Firecracker 6.22 (0.245) x 25.40 (1.000) AlNiCo-5 105
57030 Actuator for Long Firecracker 6.22 (0.245) x 38.10 (1.500) AlNiCo-5 105
57060 Actuator for Stainless Threaded Barrel Sensor M8 x 1.25 Pitch x 36.00 (1.420) AlNiCo-5 105
57065 Actuator for Threaded Barrel Sensor (Standard) (5/16 x 24) Pitch x 38.10 (1.500) AlNiCo-5 105
57070 Actuator for Threaded Barrel Sensor (Metric) M8 x 1.25 Pitch x 38.10 (1.500) AlNiCo-5 105
57075 Actuator for Heavy Duty Threaded Barrel M12 x 1.00 Pitch x 46.00 (1.810) Ceramic-2 125
RECTaNgULaR
These rectangular bare magnets and packaged actuators are ideally suited for mounting
on a flat surface. They are suitable for use in a wide range of environments, including
high-temperature applications.
CYLINdRICaL
Designed for mounting on a frame, these cylindrical bare magnets and packaged actuators are
appropriate for use in a wide range of environments, including high-temperature applications.
Magnetic Actuators
NS
Magnet
User Interface
Ice Dispenser
Reed Sensor
Electronic Control Unit
Frost Sensing
Temp Sensing
LED Light
12
Appliances like refrigerators, freezers and wine coolers are used to keep food/
beverages cold and extend their useful life. These appliances contain lights to
illuminate the inside compartments when the doors are open. However, the
lights only need to turn on when a door is open. To accomplish this, a proximity
sensor is needed to detect if the appliance door is open or closed.
A reed sensor can be used to detect the position of the door. In refrigerators, a
reed sensor is mounted to the frame of the appliance and a permanent magnet
is mounted to each door. Each reed sensor and magnet pair is positioned so
that the reed switch contacts close only when the door is completely closed.
The position of the reed sensor’s contacts can be monitored by an electronic
control unit (ECU) within the refrigerator’s electronics assembly to turn
the interior lights on and off as needed.
Reed sensors are ideal for a variety of position- and proximity-sensing
applications where there is a need to detect the presence of a moving part
in relation to a sensor in a fixed location.
PROXIMITY SENSING USING REED SENSORS—
Refrigerator Door
Figure 1-Reed sensors detect the opening of refrigerator doors
• No physical contact required
to operate the switch
• Zero power required for switch
actuation
• Electrical contacts are within
a hermetically sealed capsule
that is immune to moisture,
dust and dirt
• Wide operating temperature
range adequate for use in cold
temperatures
• Overmolded sensors provide
additional protection against
mechanical stresses and
vibration
• Low-cost alternative
to mechanical switch
Features and Benefits:
Suggested Products:
Features and Benefits:
Suggested Products:
• FLEX-14 (14 mm reed switch)
• MDCG-4 (15 mm reed switch)
• MDSR-10 (10 mm reed switch)
• 59025 (Firecracker reed sensor)
• 59140 (Flange mount
reed sensor)
Similar Applications:
Refrigerators/freezers, dish washers, washing machines, rice cookers,
coffee makers, vacuum cleaners and vending machines
Applications
Hall effect sensors can be used to detect the movement of a garage door to
stop the motor once the door has reached its open or closed position. Typically,
a system of two Hall effect sensors, each associated with its own permanent
magnet, is used to determine whether the door is completely open, completely
closed or somewhere in between.
One of the magnets is mounted on the chain drive of the garage door opener so
that it is positioned directly next to the Hall effect sensor used to detect a closed
door. The other magnet is positioned so that it moves with the chain and is located
directly next to the other Hall effect sensor when the door is completely open.
Similar to reed sensors, Hall effect sensors are ideal for position or proximity sensing
where there is a need to detect the presence of a moving part in relation to one or
more sensors in fixed locations. They offer extended life and reliability over reed
sensors since there are no electrical contacts that are opened and closed. Common
examples include door- and lid-position sensing in the similar applications listed.
PROXIMITY SENSING USING HALL EFFECT SENSORS—
Garage Door
Receiver
Power Supply
Motor Drive
Hall Effect
Sensor
Electronic Control Board
S
N
N
S
Figure 2-Garage door, Hall effect sensors mounted above garage door opener
• No physical contact required
to operate the switch
• Wide operating temperature range
adequate for use in hot and cold
temperatures
• Hall effect sensor is an integrated
circuit with no mechanical moving
components
• Encapsulated sensors provide
additional protection against
environmental/mechanical stresses
and vibration
• Reliable operation for millions
of cycles
• Low-cost alternative to mechanical
switches or infrared/optical sensors
• 55100 (Miniature ange mount
Hall effect sensor)
• 55140 (Flange mount Hall
effect sensor)
• 55310 (Flat pack digital Hall
effect sensor)
Similar Applications:
Dishwashers, washing machines, vacuum cleaners, security locks
on doors and vending machines
Littelfuse electronics product portfolio includes Hamlin
13hamlin.com | littelfuse.com
Reed switch-based sensors are used as highly effective speed sensors in low-cycle-
rateapplications with rates upto a few thousand revolutions per minute (RPM).
For example, in treadmills, a reed sensor is used to detect the speed of the moving
belt. Two permanent magnets are placed on diametrically opposite ends of the belt
pulley, and a reed sensor is mounted to the treadmill frame perpendicular to one
end of the pulley. As the treadmill pulley rotates, the reed sensor detects when
each of the magnets is close to the sensor. The time interval between the detection
of each magnet is used to compute the speed at which the pulley is rotating.
Reed sensors are highly accurate in speed-sensing applications where there
is a rotating part. They are commonly used in fitness equipment where there
is a rotating part with a variable speed.
SPEED SENSING USING REED SENSORS—
Treadmill Pulley
Display Board
Power Supply
Motor Drive
Main Motor Board
User Interface
Reed Sensor
Figure 3-Treadmill pulley
• Effective, noncontact solution
used to switch the sensor
• Digital output signal is used to
compute speed with high accuracy
• Long lifetime and reliable sensing
for millions of operations
• Low-cost alternative to infrared/
optical sensors
• Overmolded sensors provide
additional protection against
mechanical stresses and vibration
• 59025 (Firecracker)
• 59065 (Threaded barrel)
• 59140 (Miniature ange mount)
• 59150 (Flange mount)
Similar Applications:
Fitness equipment, including treadmill, stationary bicycle and elliptical
cross-trainer
Hall effect sensors make very effective rotary speed sensors. The strengths of
these sensors are their reliability, repeatability, accuracy and high speed. For
example, in a clothes washing machine, a digital or latching Hall effect sensor
can be used to detect a rotating ring magnet to determine the rotating speed
of the drum. Multipole magnets (e.g., 8–40 poles) are typically used as the ring
magnets in these designs. The frequency and resolution of speed are affected
by the number of magnet poles.
Direction, as well as speed, can be measured. The direction signal can be
provided by either quadrature signaling or with the direction encoded in the
pulse width. Quadrature signaling involves two square wave speed signals
where the direction of rotation is determined by the lead vs. lag phase
relationship between the two signals.
Another popular method of detecting speed is to use Hall effect speed sensors
to detect rotating ferrous gear teeth such as in an automotive transmission
speed sensor application. The Hall effect sensor has a back-bias magnet
and detects the variation in magnetic flux density between the gear
tooth and the Hall effect sensor.
SPEED SENSING USING HALL EFFECT SENSORS—
Washing Machine Drum Speed
User InterfaceDisplay Board
Main Motor Board
Power Supply
Main Motor
Hall Effect Sensor
Figure 4-Washing machine drum speed sensor with ring magnet
• Digital output signal is used to
compute speed with high accuracy
• Long lifetime and reliable sensing
for millions of operations
• Effective for high-speed
applications
• 55140 (Flange mount)
• 55310 (Flat pack digital)
• 55505 (Geartooth sensor)
• 55075 (Geartooth sensor)
• Custom-designed sensor
Similar Applications:
DC motors, vacuum cleaners and wheel speed
SN
Flux Concentration-Tooth Position
Single Low
SN
Flux Concentration-Valley Position
Single High
Figure 5-Geartooth sensing
Features and Benefits:
Suggested Products:
Features and Benefits:
Suggested Products:
14
Applications (continued)
Many types of security alarm systems use a reed switch/sensor attached to the frame
of the door or window. The actuating magnet is attached to the moving door or
window so that when it is opened, the reed sensor detects the moving magnet
and opens/closes its electrical contacts—sending a signal to the alarm system.
Similarly, reed switches can easily be mounted to circuit boards used in smoke
or gas alarm systems. In portable systems, such as gas detectors, the reed switch
is used to activate the system when the handheld detector or reader is placed
in the docking station. In systems with smoke/gas detectors in fixed positions,
the reed switch can be activated with a handheld magnetic wand to put the
detector in test mode.
Reed switches and reed sensors are effective solutions for many types of
security and alarm sensor applications. Examples include detecting the door
and window position, measuring the sump pump water level or activating the
test mode of a smoke detector. Reed relays can be used to activate the alarm
loop in active sensors like motion sensors and smoke detectors.
SECURITY AND ALARM SYSTEMS—
Door and Window Alarms
Alarm Driver
Power Circuit
NS
Magnet Reed
Sensor
Electronic Control Unit
Figure 6-Door alarm system using a reed sensor
• No physical contact is required
to operate the switch
• Zero power required for
switch actuation
• Wide operating temperature range
adequate for use in hot and cold
temperatures
• Electrical contacts are within a
hermetically sealed capsule that is
immune to moisture, dust and dirt
• Overmolded sensors provide
additional protection against
mechanical stresses
• Low-cost alternative to mechanical
switches
• MDSM-10 (10 mm reed switch)
• 59020 (Miniature recracker)
• 59140 (Miniature ange mount)
• 59170 (11 mm overmolded
reed switch)
• HE3621A0510 (Miniature SIL
reed relay)
Similar Applications:
Burglar systems, smoke alarms and gas detection systems
Resistive reed ladder networks are used to measure the liquid level in a tank,
which allows for a continuous output signal rather than discrete signals from
single-point level sensors. This continuous level sensor produces a variable
resistance or continuous current/voltage that is related to the position of the
float/magnet assembly. As the liquid level changes, the relative float position
follows, activating the reeds sequentially and producing the associated output
voltage or resistance value. The typical spacing between reed switches is
usually provided in 6.35 mm or 12.7 mm steps.
Littelfuse supplies full assemblies that include stainless steel or plastic
housings. Bare reed switches are also available.
Level sensors incorporating reed switch and resistance technology are
commonly used for measuring continuous liquid levels in the automotive,
marine and industrial markets. The float, which contains a magnet, moves
up or down over the sealed stem containing the reed switches/resistors.
CONTINUOUS LEVEL SENSING—
Industrial Tank Water Level
S
N
S
N
Load
+ -
DC24V
Sensor
Converter
Float
with
Magnet
R16
R15R14
R13
R12R11R4R3
R2
R3R0
S16
S15S14
S13
S12S11
S4
S3S2
S1
S0
White
(Level Signal)
Black
(Ground)
Blue
(Thermistor Single)
Empty Full
R5 R4
R3
R2
R1
Figure 7-Resistive reed ladder network for level sensing
• Continuous level output signal,
not like a single-point level sensor
• Electrical contacts are within a
hermetically sealed capsule that is
immune to moisture, dust and dirt
• Sensor housing provides protection
against mechanical stresses
and vibration
• Reliable switching for millions
of open/close operations
• Wide operating temperature range
adequate for use in hot and cold
temperatures
• MDSM-10 (10 mm reed switch)
• MDSM-4 (15 mm reed switch)
• Custom-designed level sensor
assemblies
Similar Applications:
Fluid-level sensing for: urea in diesel trucks, fuel tanks, HVAC refrigerator
tanks and condensate water tanks
Littelfuse electronics product portfolio includes Hamlin
Features and Benefits:
Suggested Products:
Features and Benefits:
Suggested Products:
15hamlin.com | littelfuse.com
When provided with a float magnet, reed sensors can function as fluid-level
sensors. For example, in a dishwasher, a float-type level sensor is used to detect
if the water level inside of the water collection pan has reached the fill limit. The
float sensor consists of a reed switch mounted within a shaft and a permanent
magnet provided within a float housing. The shaft is vertically mounted within
the water collection pan so that the reed switch is positioned at the water fill
limit of the pan. As the water level rises, the magnet within the float travels up
the shaft to the point where it comes into the proximity of the reed switch. The
reed switch senses the presence of the magnet and signals the dishwasher’s
ECU that the water level has reached its fill limit.
Level sensors incorporating reed switch technology are low-cost solutions
for any application where there is a need to detect the amount of liquid in
a tank or pan. They are commonly used in white goods and appliances.
LEVEL SENSING—
Dishwasher Water Level
S
N
ECU
Cold Water Valve Hot Water Valve
User Interface
Reed Sensor
Floating Magnet
Pump Control Temp Sensor
Figure 8-Float sensor detecting water level in a dishwasher
• No physical contact required
to operate the switch
• Zero power required for switch
actuation
• Electrical contacts are within a
hermetically sealed capsule that is
immune to moisture, dust and dirt
• Wide operating temperature range
adequate for use in hot and cold
temperatures
• Sensor housing provides protection
against mechanical stresses
and vibration
• Reliable switching for millions
of open/close operations
• 59630 (Float sensor)
• FLEX-14 (14 mm reed switch)
• MDSR-10 (10 mm reed switch)
• MACD-14 (14 mm reed switch)
• 59300 (Level sensor)
Similar Applications:
Dish washers, washing machines, air conditioners, dehumidifiers and
coffee brewers
A flow switch utilizes a reed switch to detect the motion of a valve, paddle
wheel or piston that is fitted with a permanent magnet. For example, in some
tankless water heater units, the flow sensor contains a permanent magnet that
is fixed to a piston that moves when there is water pressure present in the
system. As the water pressure increases, the piston movement brings
the magnet into the proximity of the reed switch. This causes the reed switch
to close and signals the presence of water flow.
A flow sensor utilizes a turbine with an attached magnet that rotates by a fixed
reed switch or Hall effect sensor. The speed at which the turbine rotates is
proportional to the flow rate of the fluid.
Reed sensors are highly effective solutions for flow-sensing applications
where there is a need to detect the presence of liquid or gas flow in a system.
Common uses include water or gas flow in the similar applications listed.
FLOW SWITCH—
Tankless Water Heater
User Interface
Power Circuit
ECU
Outlet
Inlet
Water Flow
Ignition Circuit
Reed Sensor
NSNS
Figure 9-Flow detection in a tankless water heater
• No physical contact is required
to operate the switch
• Zero power required for switch
actuation
• Wide operating temperature range
adequate for use in hot and cold
temperatures
• Electrical contacts are within a
hermetically sealed capsule that is
immune to moisture, dust and dirt
• Overmolded sensors provide
additional protection against
mechanical stresses
• Reliable switching for millions
of open/close operations
• MDSM-4 (15 mm reed switch)
• MLSM-4 (15 mm reed switch)
• MDCG-4 (15 mm reed switch)
• MDSR-10 (10 mm reed switch)
• 59165 (16 mm overmolded reed switch)
• 59170 (11 mm overmolded reed switch)
Similar Applications:
Dish washers, washing machines, hot tubs and utility gas meters
Features and Benefits:
Suggested Products:
Features and Benefits:
Suggested Products:
a BROad & dEEP PORTFOLIO
Littelfuse offers the world’s broadest and deepest portfolio of circuit protection
solutions. Our extensive knowledge and experience in circuit protection
technologies are accessible to our customers around the globe. If you have a
unique circuit protection problem, we have the expertise and resources needed
to develop a solution that delivers exceptional safety and reliability. Our global
research and development teams are constantly working on innovative circuit
protection technologies designed to safeguard the latest products on the market.
Over-Current Protection
• Fuses
• Resettable positive temperature coefficient (PTC) devices
Over-Voltage Suppression
• Gas discharge tubes (GDTs) • TVS diode arrays
• PLED Series open LED protectors • SIDACtor® devices
• PulseGuard® ESD Suppressors • Switching thyristors
• TVS diodes • Varistors
LITTELFUSE OFFERS CIRCUIT PROTECTION…
Littelfuse circuit protection products can be used with Hamlin reed switch and sensor products to enhance safety and reliability in various
load-switching applications. We recommend using circuit protection for the following examples of load switching:
Inductive Load Switching – Arc suppression is recommended to maximize the operating life of inductive loads. For DC loads, a diode should
be used. For AC loads, a transient voltage suppression (TVS) diode, a metal oxide varistor (MOV) or a resistor-capacitor (RC) suppression
device may be used. MOV and RC suppression devices should not have too much capacitive inrush current as described below.
Capacitive Load Switching – Capacitance in the load circuit or long cables may cause permanent or intermittent contact sticking.
Contact protection is recommended if the energy stored in the capacitor (E = ½CV2) is greater than 1 µJ. Use a small value resistor
in series with the reed switch for contact protection.
16
Beyond Sensing...
Fuse Blocks
Fuse Clips
Fuse Holders
Fuses
SIDACtor®
Devices
TVS
Diode Arrays
PLED
LED Protectors Switching
Thyristors
Varistors
LF-Hamline-V23.indd 18 1/28/15 1:49 PM
gLOBaL FOOTPRINT…
At Littelfuse, our mission is to develop innovative circuit protection, power
control and sensing solutions that meet our customers’ unique needs.
This customer-focused philosophy has helped us become the top circuit
protection brand in the world.
Our industry-leading product portfolio includes reliable circuit protection, power
control and sensing products that are designed for a variety of applications. We have
assembled unparalleled expertise and developed a global footprint that puts our
facilities close to our customers and target markets. As our global manufacturing
and R&D teams objectively recommend the best circuit protection, power control or
sensing solution for each customer application, they form partnerships that will lead
to the development of the next generation of advanced products.
TVS Diodes
Resettable
PTC Devices
Gas Discharge
Tubes
PulseGuard®
ESD Suppressors
©2015 Littelfuse, Inc. Specications, descriptions and illustrative material in this
literature are as accurate as known at the time of publication, but are subject to
change without notice. Visit www.littelfuse.com for more information.
LF-Hamline-V23.indd 19 1/28/15 1:49 PM
