Light-controlled lighting with triac (1)

Similar to the circuit introduced in the previous section, the photoresistor RG and the fixed
resistor Rl also form a voltage divider. The light-emitting diodes
LED 1 and LED 2 here also serve as power indicators and rectifier
triggers. When the alternating current is in the upper and lower positive half cycle, LED2
is turned on (of course at night) to provide a positive trigger current to vs.
When the alternating current is in the upper and lower negative half cycle, LED1 is turned on (it should
also be at night ) provides reverse trigger current to vs. During the day,
the indoor natural light is strong. RG has low resistance and low partial voltage value, vs cannot be turned on and the light H does not light up. Only
when night falls, the partial voltage value is higher. This AC voltage is added to the control electrode of the thyristor vs through LED1 and LED
2, so that vs is turned on, and the lamp H lights up normally. RP can be used to adjust the sensitivity of the light control.