The optocoupler is used for signal transmission between two galvanically isolated circuits. Electrical input signals are converted into light signals and finally back into electrical signals. In principle, it is possible to transmit both digital and analog signals. Optocouplers are often used in communication, control and monitoring systems.
In contrast to fork couplers and light barriers, optocouplers have opaque housings. Optocouplers usually consist of two main components: an optical transmitter and an optical receiver. Light-emitting diodes and laser diodes usually act as optical transmitters. Photodiodes or phototransistors serve as optical receivers.