Light control light lighting circuit

The 220V AC voltage is stepped down by the capacitor C1, the rectifier bridge stack UR performs full-wave rectification, the capacitor C2 filters, and the voltage is stabilized by the Zener diode and becomes a DC voltage.

The resistance of the photoresistor RG is very small during the day, and the pulse signal charging the capacitor C3 is very small, which cannot trigger the thyristor to conduct. The circuit of the bulb EL is blocked, and the bulb EL does not light up: when night falls, the dark resistance of the photoresistor is very large, and the capacitor C3 is charged. The pulse signal is very large, which can trigger the gate of the thyristor, causing the thyristor to conduct. At this time, the relay coil is energized, and the normally open contact of the relay in the EL circuit of the light bulb is connected, and the light bulb EL lights up.

Adjusting the potentiometer RP can adjust the size of the trigger signal to the gate, thereby adjusting the conduction angle of the thyristor, thus controlling the brightness of the bulb.