A logic optocoupler, also known as a digital optocoupler, is a device that uses optical isolation to transfer a digital logic signal between circuits while keeping them electrically isolated.Some key points about logic optocouplers include that they contain a light-emitting diode (LED) and a photosensitive transistor enclosed in a package.The input LED converts an incoming logic signal into modulated light and this light is detected by the output phototransistor.The phototransistor then converts the light back into electrical logic output.