An automotive relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple control signals, and a set of output terminals which are connected to the device to be controlled. Generally, relays are used to control a large amount of current with a small signalling current. They are also used to protect circuits from overloads. Common automotive applications of relays include electric windows, electric fans, headlights, and fuel-injection systems. Relays can also be used to control on/off and high/low power functions in a vehicle. Automotive relays are essential components of modern vehicles, increasing efficiency, providing added reliability, and promoting safer operation.