Solid state relays (SSRs) are electrical switching devices that serve the same purpose as electromechanical relays but without the moving parts, hence the name 'solid state'. From having no moving parts, SSRs tend to hand longer operational lifetimes as they are not subjected to wear & tear. They are capable of performing switches faster than their electromechanical counterparts as they use the electrical and optical properties of semiconductors to perform the switching functions. RS carry an extensive range of solid state relays from trusted brands, including Carlo Gavazzi, Celduc, Omron, Panasonic, Siemens, Sensata/Crydom, and many more.
The main advantages of solid state relays over conventional electro-mechanical relays is that they have no moving parts to wear out, and therefore no contact bounce issues. SSRs are able to switch both “ON” and “OFF” much faster than a mechanical relay's armature can move, as well as zero voltage turn-on and zero current turn-off eliminating electrical noise and transients. For more information about solid state relays, please see our comprehensive guide to solid state relays.
Solid state relays are available in a range of package options, ranging from just a few volts or amperes to many hundreds of volts and amperes of output switching capability. A small input voltage, typically 3 to 32 volts DC, can be used to control a much large output voltage or current.