光敏器件包括光敏电阻、光敏二极管及光敏三极管等。光敏器件可以用来以可见光或红外光的形式控制报警器、测试仪、自动开关、继电器等多种装置或执行机构。因此光敏器件在自动化技术中起着极其重要的作用。-Photosensitive devices, including photosensitive resistor, photodiode and phototransistor, etc.. Photosensitive devices can be used to visible light or infrared light form of control alarm, tester, automatic switches, relays and other devices or implementing agencies. Therefore a photosensor in the automation technology plays an extremely important role.