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Reed Switch Specifications and Manufacturers

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This page covers the basics of reed switches, including their technical specifications, and provides a list of reed switch manufacturers or vendors.

Reed switch specifications include pull-in, drop-out, maximum switching voltage, maximum switching current, and maximum switching power.

What is a Reed Switch?

  • A reed switch is a magnetically activated mechanical switch.
  • It consists of two metallic contacts enclosed in a small enclosure, usually a glass capsule.
  • The contacts are magnetic and move in response to a magnetic field. A permanent magnet is needed to activate the switch.
  • There are two main types of reed switches: SPST (Single Pole Single Throw) and SPDT (Single Pole Double Throw). The most common type is SPST, which can be either normally open or normally closed.

Reed Switch construction and symbol

Figure 1: Reed switch construction and its symbol.

Reed switches are available in the following configurations:

  • Normally open
  • Normally closed
  • Bistable

Reed Switch Specifications

The following specifications are important to consider when selecting a reed switch:

  • Pull-in: The minimum magnetic field strength required to activate the switch, often measured in ampere-turns. In other words, it’s the magnetic field strength at which the reed switch is activated.
  • Drop-out: The maximum magnetic field strength at which the contacts of the switch relax. In other words, it’s the magnetic field strength at which the reed switch is de-activated. This is also measured in ampere-turns. The pull-in value will always be higher than the drop-out value.
  • Maximum Switching Voltage: The maximum voltage at which the contacts can be switched. This is a reference voltage used to determine contact switching performance.
  • Maximum Switching Current: The maximum current at which the contacts can be switched. This is another reference used to determine contact switching performance.
  • Maximum Carry Current: The maximum current that can flow continuously through the closed contact.
  • Maximum Switching Power: A reed switch can be used with alternating current. Hence, its switching capability may be expressed in watts (W) or volt-amperes (VA).

Reed Switch Manufacturers

The following table lists popular reed switch manufacturers or vendors:

Reed switch ManufacturersDescription
HSI Sensing, 3100 NORGE ROAD, CHICKASHA, OK 73018, USAThis company manufactures reed switches for various applications across different industries. They offer reed switches of different types: form A (SPST, normally open), form B (SPST, normally closed), and form C (SPDT, single pole double throw, break before make).
Littelfuse Inc. Chicago, IL, 60631 USAThis company offers a wide range of magnetically operated reed switches. They are available in bare glass and overmolded packages with a variety of specifications (mechanical, electrical, magnetic).
Reed Relays and Electronics India Limited, Anekal-Gumlapuram Road, Thally 635118, IndiaThis company manufactures reed switches for various applications with round glass tubes and wire to achieve maximum seal strength.
Standex Electronics, Inc.This company offers magnetic reed switches designed to address various specific applications, including high-frequency reed switches, high-voltage reed switches, high-power reed switches, SMD reed switches, and more.
STG GermanyThis company offers reed switches with glass tubes ranging from 7 to 50 mm in length. The switches are available for switching capacities up to 120 W/VA, switching voltages from 0 to 10KV AC/DC, and switching currents from 0 to 3 A AC/DC.
Comus International, NJ, USAComus International manufactures reed switches of different types.