An electrical relay is an electromechanical switching device used to control a circuit that operates at a higher power level than the control circuit itself. This mechanism utilizes an electromagnetic principle, where a low-current signal energizes a coil, which in turn moves an armature to physically open or close contacts within the device. This function provides electrical isolation between the low-voltage control signal and the high-voltage load circuit, thereby allowing delicate electronics to safely manage substantial electrical loads. Relays are fundamental components in automation, control systems, and industrial machinery due to their reliable, controlled, and isolated switching capabilities.