Light automatic regulator circuit diagram

As shown in the figure, this circuit can automatically adjust the light brightness according to the intensity of external light. If the outside brightness is high, the light will be dark; if the outside brightness is low, the light will be bright. In the figure, a full-wave phase control circuit is composed of thyristor VT1 and diodes VD1~VD4, and neon tube N is used as the trigger tube of VT1. Adjusting W can change the charging time constant of capacitor C, that is, change the conduction angle of VT1 and control the brightness of the light.