Household light-controlled desk lamp circuit

The working principle circuit is as shown. The 220V AC voltage is stepped down by the capacitor cl, fully rectified by the rectifier bridge stack U],
filtered by the capacitor Cz, and stabilized by the voltage stabilizing plate tube, and then becomes a DC voltage. :
    The resistance of the photoresistor RG is very small during the day, and the pulse signal charging to the electric charger G is very small, which cannot trigger the thyristor to conduct. The circuit of the light bulb EL
is blocked and the light bulb EL does not light up. When night falls, the dark resistance of the photoresistor is very large, causing the thyristor to turn on. The charging pulse signal of the capacitor C is very large, which can trigger
the gate of the thyristor, causing the thyristor a to conduct. At this time, the relay coil is energized. 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 resistor RP can adjust the trigger signal to the door panel to be too small, thereby adjusting the conduction angle of the maximum tube, thereby controlling the brightness of the bulb
. ,.