Reed Relays Offer Switching of AC and DC Small Signals


Hermetically sealed switching solution for systems requiring no-leakage current, or operating in harsh environments requiring galvanic insulation

Littelfuse, Inc. introduced an expanded reed relay product portfolio that extends voltage capabilities to include AC ratings, supports AC or DC loads up to 300 Vdc, and provides input/output isolation voltage 2500 VRMS.

These miniature reed relays are available in single In-line (SIL) and dual-in-line (DIL) packages.

Typical applications for the reed relays include position and speed sensing in a broad array of markets:

  • Security systems

  • Fire and safety

  • Instrumentation

  • Telecom

  • Automatic test equipment (ATE)

  • Process control systems

The new reed relaysoffer these key benefits:

  • Capable of switching speeds up to 1 kHz and billions of operations.

  • Hermetically sealed switch contacts are unaffected by and do not affect their external environment.

  • Lower power coil consumption than competing electromechanical devices

  • Very low circuit board space requirement due to miniature DIL and SIL packages.

  • No leakage in the off state, making them an ideal choice for battery-powered devices.

How It Works

A reed relay combines a reed switch with a coil into one package to serve as a smaller, more power-efficient alternative to other types of relays. In comparison to solid-state relays (SSRs), reed relays provide no leakage current and higher robustness against transient spikes. Reed relays also have a much longer life, smaller size, higher switching speeds, and lower power consumption than electromechanical relay switches.

Reed relays are used for switching of loads with up to 2500 V isolation between the low-voltage control signal and load circuit. Reed relays come in a hermetically sealed miniature package and offer full galvanic (zero leakage current) load disconnect that provides the high reliability needed in harsh environment applications to switch AC/DC signals and loads. It is also well-suited for switching analog signals in test and measurement, audio, and high-frequency applications.

The HE3300 and HE3600 SIL and HE700 DIL Reed Relays are available in bulk in quantities of 2,000. Sample requests may be placed through authorized Littelfuse distributors worldwide. For a listing of Littelfuse distributors, please visit

For More Information
Additional information is available on the Reed Relay product pages.