Light-controlled street light circuit using TWH8778 (2)

It is a light-controlled automatic street light made of TWH8778 power switch integrated circuit. Its circuit is relatively
simple and its power is very good. 220V AC power is rectified by VDl-~VD-1, R. Voltage reduction and current limiting 'VS1 stable cooking
outputs 12V DC voltage for powering the TWH8778 integrated circuit. During the day, the resistance
of the photoresistor RP is much smaller than R
when exposed to natural light . The level of pin ⑤ of the TWH8778 control terminal is lower than 1 6V. The internal electronic meter is disconnected, the transistor VT is in the off state, and the light E does not light up. When the light goes off and turns black in the evening , the RI_ resistance begins to increase, causing the level of pin ⑤ of TWH8778 to rise. When it rises to 1_6V, the electronic switch inside the integrated block is turned on, that is, pin ① is connected to pins ② and ③, and the thyristor VT post R. The forward trigger current amplitude is obtained and turned on, and the street lamp E is energized and emits light. If you want to adjust the light control sensitivity of the fU circuit, you can appropriately change the resistance value     of resistor R. The function of the voltage regulator tube vs is to ensure that the voltage applied to the fifth pin of TWiIB778 does not exceed 3V when it becomes completely dark to ensure the safety of the integrated circuit and not be damaged.