A relay is an electrically operated switch that uses an electromagnet to control the opening or closing of a circuit. The 12V relay, specifically, operates at 12 volts of DC (direct current), making it suitable for applications where low voltage power sources are available, such as in automotive or battery-powered systems. The 12V specification means the relay is designed to be triggered by a 12V electrical input, often from a microcontroller or another small electrical signal.

    The basic construction of a 12V relay consists of several key components： an electromagnet (or coil), an armature, and a set of contacts. When the coil is energized by a 12V current, it generates a magnetic field that pulls the armature, which in turn opens or closes the electrical contacts. The contacts can be "normally open" (NO) or "normally closed" (NC), allowing the relay to control a circuit by either completing or interrupting the current flow based on the relay's state.