At its core, a general-purpose relay is an electromechanical device that operates as a switch. It comprises an electromagnet, a set of contacts, and a spring mechanism. When electrical current flows through the coil of the relay, it generates a magnetic field that attracts a movable armature, causing the contacts to either connect (closing the circuit) or disconnect (opening the circuit). This allows a small input current to control a larger output current, facilitating the management of devices that require higher voltage and power levels, such as motors, lights, and other electrical appliances.