The ITR20403 opto interrupter from Everlight is an electronic part designed to detect objects or other materials that interrupt an infrared light beam. It consists of an infrared LED and a photosensitive transistor, with a space between them to allow for the interruption of light. The interruption of the light is detected by the transistor, and sent as an electrical signal indicating that presence or absence of an object. The reflective-type opto interrupter also has a light reflection pattern that allows it to better detect objects that are close by. It is a compact design that makes it a great choice for use in smaller electronic products, and it is RoHS compliant for use in Europe and other areas of the world. The device is suitable for use in many electronic applications, including access control systems, security, and automation.