A relay isolates a low-power control circuit from a high-power load circuit. In a traditional electromechanical relay, current passing through a coil generates a magnetic field that physically pulls a set of contacts closed or open. Solid-state relays perform the same function using semiconductors like thyristors or optoisolators, eliminating moving parts and contact bounce.
Heard on the job
I can hear the main power relay clicking, but the motor isn't getting any voltage.
Also heard as
- contactor