A relay is an electrically operated switch used to control the flow of electricity in a circuit. It consists of an electromagnet (or coil), an armature, contacts, and a spring mechanism. When an electric current passes through the coil, it creates a magnetic field that attracts the armature, which then moves to open or close the relay's contacts. This mechanism allows a low-voltage, low-current signal to control a high-voltage, high-current circuit, making relays invaluable in systems requiring precise control and automation.

    Relay assemblies, as the name suggests, refer to the configuration and interconnection of multiple relays to form a larger control system. These assemblies are designed to operate in various conditions, such as time-sensitive control, safety functions, and remote switching.