A 12V DC relay is a type of relay designed to operate with a 12-volt direct current (DC) input. It consists of several key components: a coil, an armature, a set of contacts, and a spring. When a voltage is applied across the coil, it creates a magnetic field that attracts the armature. This movement either opens or closes the contacts, thereby controlling the flow of electricity to a different circuit. The operation is completely mechanical but is controlled electronically via the low-voltage input.

    The main advantage of using a relay is that it allows a low voltage circuit to control a high voltage circuit without directly connecting the two. This is particularly useful in automation, control systems, and various electronic devices that require switching operations.