A Relay is an electrically operated switch – most commonly electro-mechanical, but options also exist for solid-state. A low-power signal operates the coil, which then engages the contacts and transmits power the end device. Many options exist for numbers of poles and throw configurations, as well as time-delay relays, latching relays, and other functions – even including programmable logic actions in the specific case of “Smart Relays”. When switching power directly to a motor, a Relay is known as a Contactor.