White Paper: Choosing the Correct Relay for Your Application
A relay is a switch powered by a relatively small electric current that can turn a much larger electric current on or off. Essentially, relays are power-switching solutions that can be used to allocate power without manually opening or closing a switch. To switch power on and off, a relay simply requires a small electrical signal. The ability to have low-power control over a high-power signal makes relays a major component throughout the history of electronics.