Photocouplers consist of an infrared LED (emitting device) and a photosensitive receiving device optically coupled into the same package. What this does is allows electrical signals to be passed from the input to the output circuit; separated by an isolation barrier that is designed to withstand high voltage levels. This find it's way in many applications for safety reasons, as well as to prevent the damaging of expensive or important electrical components. For more detailed technical information, feel free to reach out to us at American Bright!