A photosensitive diode is installed on the surface of the switch panel, and a cylindrical microphone is installed inside. The photosensitive effect of photodiode only works when it is dark. When the color darkens to a certain extent, the photodiode will generate a pulse current on the electronic circuit board after induction, so that all circuits of the photodiode are closed. As long as there is noise, the cylindrical microphone will also generate pulse current, and then turn on the acousto-optic control switch circuit to work.

Acousto-optic switch is a switch controlled by sound and light. When the brightness of the environment reaches below a set value and the noise of the environment exceeds a certain value, this switch will be turned on.

Selection of acousto-optic switch:

Mainly applicable to tungsten lamp. The reason is that the acousto-optic switch is started by electronic circuit, and the lamp with rectifier is easy to cause the breakdown of electronic components due to the large starting current, which leads to the switch damage.