Circuit works: This light control automatic street lamp circuit is the capacitor C1, C2 and diode VD1 ~ VD4 composed of capacitor buck, bridge rectifier circuit, R1, R2 is the discharge resistance. The regulator diode VD5 stabilizes the pre-rectified voltage within 12 V as the operating voltage of the NE555. C3 is the power supply filter capacitor, which effectively suppresss the ripple of the rectified voltage and obtains a smooth DC voltage. Circuit NE555 connected into a bistable circuit, photosensitive resistor RC and potentiometer RP to form a simple voltage divider, NE555 ② feet, ⑥ feet connected to the divider point. During the day, the light is bright, the photoresistor RG has a low resistance state, for which the partial pressure point is high. When the ⑥ pin voltage above 2/3 power supply voltage, the bistable circuit reset, NF555 output ③ pin for the low potential, the relay K does not work, street light L does not light. When the night falls, the photoresistor RG exhibits a high resistance due to the absence of light, and the divider point is low. When the NE555 ② pin potential below the l / 3 power supply voltage, the bistable circuit is set, NE555 ③ pin output high potential, following a practical light control switch automatic control circuit circuit electrical work, Its normally open contact K1 contact pull, street light L power light. The diode VD6 is connected in parallel at both ends of the relay coil to protect the integrated circuit from the self-inductance electromotive force of the coil. Here is the NE555 date sheet.

Component selection and debugging: Diode and RC components are marked by the value of the icon. Fine-tuning potentiometer RP, because it can change the voltage level of the divider point, it can adjust the sensitivity of light control, so that when we need to light when the lights shine. Specific debugging, RP should first spin to the maximum resistance, the photoresistor RG on the equivalent of the night at the dark, with good insulation performance of the cross screwdriver slowly fine adjustment of small RP, to a certain location, the relay K pull, street light glow.There are many electronic component distributor here.

Remember: the power of the selected lamp should not exceed 60 w.

Reference: ECW-U1C124JB9 VS-T40HF40