A relay is an electrically operated switch that uses an electromagnet to open or close a circuit. The term "12-volt relay" refers to the type of relay that is typically powered by a 12-volt electrical system. The relay consists of a coil, a set of contacts, and an armature. When a small electrical current flows through the coil, it creates a magnetic field that pulls the armature, either making or breaking the connection between the contacts. This simple mechanism allows the relay to control larger amounts of current with a much smaller signal.

    12-volt relays are commonly used because 12 volts is a standard voltage in many systems, especially in automotive and industrial applications. Vehicles, for example, rely on 12-volt electrical systems, making 12-volt relays perfect for tasks such as controlling headlights, motors, and air conditioning systems.