A 12V DC relay is an electromagnetic switch that is activated by an electrical current of 12V DC (direct current). It essentially acts as a bridge between different circuits, allowing a low-power signal to control a higher-power circuit. The relay operates on the principle of electromagnetism: when current flows through the coil inside the relay, it creates a magnetic field that attracts a movable armature, causing the switch to either open or close, depending on the configuration.

    The relay consists of several parts: a coil, contacts (typically NO or NC), a movable armature, and a spring mechanism. When the coil is energized with the 12V DC signal, the armature moves, opening or closing the contacts to complete or break the circuit. This allows a low-voltage control circuit to switch high-voltage devices, such as motors, lights, or even industrial machines, without risk of damaging the control circuit.