Relay Pin Description June 2, 2019 5V Relay: Pinout, Description, Working & Datasheet. Relays are most commonly used switching device in electronics. Let us learn how to use one in our circuits based on the requirement of our project. components101.com 30 Amp 240 Volt Outlet250 Volt Plug WiringCopper Light SwitchGoodman Furnace Thermostat WiringHome Electrical Wiring Guide220 Volt Wiring DiagramCeiling Fan Circuit DiagramThree Pin Plug Wiring