A Switch Relay is an electrically operated switch that can control one or more circuits. When an electric current is applied to the relay's coil, it creates a magnetic field, causing mechanical movement of internal contacts. This movement either opens or closes the circuit, thereby switching the connected load on or off. In simple terms, a relay acts as a remote control switch, allowing you to control high-power devices with low-power signals.

    There are two main types of relays： electromechanical relays and solid-state relays. Both serve the same basic function but differ in construction, functionality, and application.