What is a photoelectric switch?

What is a photoelectric switch?

The photoelectric switch is a component that is packaged together by a light emitting tube and a light receiving tube,and is widely used in various control circuits of computer, audio and video industry.There are two common photoelectric switches,one for transmission and the other for reflection.Compared with the two,the transmission-type photoelectric switch has higher sensitivity,but sometimes it is not as convenient as the reflective switch.Most of the photoelectric switches adopt the structure that the input and the output terminals are mutually isolated,that is,the transmitting tube and the receiving tube are independent from each other,and the electrical insulation is maintained.But there are a few products using non-isolation,that is,the launch tube and the receiving tube for the common ground. Figure 9-1 shows the appearance and internal structure of the common transmission and isolation photoelectric switches.It can be seen from the diagram that when the voltage is applied to the transmitting tube,the emitter tube emits light,and if at this time,there is no covering between the transmitting tube and the receiving tube, the receiving tube can receive the light,the internal resistance changes,and the cover changes.