A relay is an electromechanical switch that is activated by an electrical current. It consists of a coil, an armature, a set of contacts, and a spring. When a current flows through the coil, it generates a magnetic field, which attracts the armature and changes the position of the contacts. This action allows the relay to control the connection between two electrical circuits, often enabling the switching of high-voltage or high-current loads using a low-voltage control signal.

    Relay circuits are widely used in applications that require remote control, automation, or isolation between circuits. In many cases, relays are employed to protect sensitive components from overloads, control lighting systems, or automate machinery in industrial settings. The flexibility and reliability of relay circuits make them indispensable in modern electrical systems.