By OMRON Automation.
A solid-state relay (SSR) is an electronic switching device that switches on or off when a small external voltage is applied across its control terminals. SSRs consist of a sensor which responds to an appropriate input (control signal), a solid-state electronic switching device which switches power to the load circuitry, and a coupling mechanism to enable the control signal to activate this switch without mechanical parts. The relay may be designed to switch either AC or DC to the load. It serves the same function as an electromechanical relay, but has no moving parts.
OMRON has been leading the world in relay technology for more than 50 years, maintaining the industry’s broadest relay product line. Our large, dedicated relay
R & D budget allows us to produce a steady stream of innovative relays that perform in different operating environments and industries. Companies around the world depend on OMRON to provide ingenious solutions to their most challenging applications, including applications ideal for solid state relay.

OMRON line of solid state relays includes more than 20 different models with hundreds of variations and options. These relays have flexible input and output
ranges and multiple footprints providing a reliable solution to any application.
Benefits of Solid State Relays
- Life expectancy significantly greater than electromechanical relays
- Contains no moving parts or contacts to wear out
- Immune to contact bounce and arcing
- No audible clicking
- Provides clean switching which generates very little electromagnetic interference
- Solid State Relays provide up to 10 times the shock resistance of electromechanical relay
- High I/O isolation that is crucial for isolating sensitive equipment from the load
- Minimize surge and input noise
- Simplified wiring
When should you use a Solid State Relay?
- When long life is required
- When the relay must operate in a harsh environment (i.e. dust, humidity, or a combustible environment)
- When silent operation is preferred
- When high speed switching is required
- When limited source current is available to drive the input
- When compatibility with digital logic is required,
- such as with microprocessor or PLC controlled
- applications