Light control open light street lamp automatic control circuit principle

The working principle of the circuit: the circuit of the light-controlled automatic street lamp is a capacitor B1, C2 and a diode VD1 ~ VD4 to form a capacitor step-down, bridge rectifier circuit, R1, R2 are bleeder resistors. The Zener diode VD5 stabilizes the pre-rectified voltage within 12V, which serves as the operating voltage of the NE555. C3 is the power supply filter capacitor, which can effectively suppress the ripple of the rectified voltage and obtain a smooth DC voltage. In the circuit, NE555 is connected to a bistable circuit. The photoresistor RC and the potentiometer RP are composed of a simple voltage divider. The 2 feet and 6 feet of the NE555 are connected to the voltage dividing point. During the day, the light is brighter, and the photoresistor RG is in a low-resistance state, so the voltage dividing point is high. When the voltage of pin 6 is above 2/3 power supply voltage, the bistable circuit is reset, the output pin of NF555 is low, the relay K does not work, and the street lamp L does not emit light. When the night falls, the photoresistor RG exhibits high resistance due to no light, and the voltage dividing point is low. When the potential of the 2 pin of NE555 is below the power supply voltage of l/3, the bistable circuit is set, and the 3 pin of NE555 outputs high potential. Following the practical operation of the light control switch street lamp automatic controller circuit diagram of Figure 1, the electric device K works. The normally open contact K1 contacts are attracted, and the street lamp L is energized to emit light. The diode VD6 is connected in parallel across the relay coil to protect the integrated circuit from the self-induced electromotive force of the coil.

Component selection and debugging: Both the diode and the RC component are referenced by the icon. The trimmer potentiometer RP can adjust the sensitivity of the light control point because it can change the potential of the voltage dividing point, so that the street lamp can be powered on when we need to light up. For specific debugging, first turn the RP to the maximum resistance, place the photoresistor RG in the dark light equivalent to the night, and slowly fine-tune the small RP with a cross-driver with good insulation performance. When measuring to a certain position, the relay K pulls in and the street light shines.

Remember: The power of the selected bulb must not exceed 60 w. As long as the wiring is correct... Interested readers and authors may wish to give it a try.