Relays, General Purpose
(a.k.a. general purpose relay, ice cube relay, plug-in relay, power relay, industrial relay, mechanical relays, control relays)
The basics: a relay is used to open and close a switch based on the input signal applied to a coil. General purpose relays are used in applications that need high power control and are generally used for isolating one voltage from another. These relays plug into sockets and are available in panel or DIN rail mounts.