Features: This switch uses photoresistor to sense intensity of light and good quality relay can directly control load. Adjust potentiometer to change sensitivity and set relay start threshold; when it is darker than the threshold, relay is energized; when it is brighter than the threshold, relay is de-energized. 12V power supply input special for relay, designed with 78L05 regulated transistor, more stable and reliable. Optical coupling isolation drive relay can effectively protect chip and ensures a better performance. Widely used for light detection, brightness detection, all kinds of light detection switch, controlling street lamps, and automatic equipment. Specification: Voltage: 12VDC Current: >100mA Load Capacity: 250V 10A AC; Or 30V 10A DC PCB Size: 5*2.6cm/1.96*1.02" Instruction: 1, Photosensitive resistance module is sensitive to ambient light, commonly used to detect the brightness change of ambient light. 2, Relay module is energized when ambient light is darker than set threshold; COM and NO terminals are connected. Relay module is de-energized when ambient light is brighter than set threshold; COM connect to NC terminal. 3, COM, NO and NC terminals are equivalent to a three-way switch. When relay coil is energized, COM is connected to NO terminal. When coil is not energized, COM is connected to NC terminal. Package Includes: 1 x P ho toresistor Switch