A photo sensor is a most important part in many electronic products, converting light into electrical signals. Its main functions are to detect light or the absence of it, to measure the intensity of light and also to use changes in lighting levels in order to carry on different processes automatically. Technologically superior factors found within photo sensors include a wide spectral response range, high sensitivity, and low power consumption. This combination makes photo sensors useful in many applications: from consumer electronics mentioned earlier--such as automatic doors with the ability to talk back its decisions and light switches who actually think for themselves--to very complicated industrial equipment which can be retooled overnight like Muon Analyzers for Mining or Optical Communication Systems in 1976. Technologically-advanced photo sensors have a wide spectral response range, high sensitivity and low power consumption. They are compatible with various circuit configurations and are suitable for different wavelengths of light including ultraviolet, visible as well asvcessive Before the development of photo sensors, automatic doors and lighting were the exclusive domain of control devices. Now it's possible to use photo sensors in such application areas as disc washing machines and magnetic field hysteresis measurement equipment.