The functionality of photoelectric sensors is based on the exploitation of the phenomenon of light absorption, reflection, refraction or scattering on different materials and surfaces, which consist of a variety of raw materials and plastics such as metal, glass or plastic.

These sensors consist of a transmitter that generates a beam of light and a receiver that detects the light beams reflected or scattered by the object. Some sensor models also use a special optical system that directs and focuses the light beam onto the surface of the object.