Why We Use Relay In Circuit April 3, 2019 How to use a relay, the easy way . Ever wondered how to use a relay? Check this vid out! www.youtube.com Different Kinds Of RelaysLight Circuit Wiring24 Volt Relay Switch12v Trailer LightsComputer Cable Color CodeBlack Screw On Light SwitchDifference Between Schematic Diagram And Wiring DiagramHow A Relay Works 12v