... 3 wires,AC 2/3 wires; 3.CE certification. SG series Photo Switch,Photoelectrical Sensor 1, Principle:photoelectric sensor ... Widely used in process controling and monitoring system for spacing,positioning detection,auto counting,speed and auto protection ... , Coulometer, Voltage Meter, Ampere Meter, Counter, Tacho Meter, Frequency Meter, flowmeter,Timer,Timer Relay, Solid State Relay, Proximity Sensor ...