A relay module is an electrically operated switch that allows a low-power electrical signal to control a high-power circuit. It consists of a relay, a protection diode, a coupling capacitor, and a transistor that drives the relay coil. The relay coil creates a magnetic field that operates the switch contacts inside the relay, which can be normally open (NO) or normally closed (NC), to control the flow of electrical current. Relay modules are widely used in various applications to automate lights, appliances, HVAC systems, and industrial control systems, among others.
