Street lights are very useful devices. They provide light automatically during the night. Street LED lights use LEDs instead of incandescent lamps. Here is the simple circuit for street lightning. The solar street light is the advanced version of the ordinary street light.
Street Light Circuit Diagram

Components Required for Street Light Circuit
- Rectifier (Step Down Transformer, Diodes-4, Capacitor-470μF)
- LDR (Light Depended Resistor)
- Resistors (56KΩ,100Ω)
- Transistor BC187 (2)
- 6V or 12V Relay
- Bulb
Working Principle of Street Light Circuit
- The bulb is Off during day time and it turns on automatically at night
- The unique property of LDR (Light Depended Resistor) is utilized here
- LDR is a variable resistor. It has very low resistance in the presence of light and very high resistance in the absence of light
- In this circuit, we have created a potential divider with 1 arm is an ordinary resistor and another arm being an LDR
- As we know that voltage drop across a resistor increases when resistance increases
- Here the drop across the LDR varies as light intensity changes That are voltage drop across the LDS is minimum in the Light and maximum in the absence of light
- The drop across the LDR is connected to the Base of the BC 187 transistor In the dark, the drop is very high (> 0.6V) and it is sufficient to turn on the transistor
- When 1st transistor is On next one will also turn on when the relay coil energizes and the bulb will glow
- In the Light, the drop is very small (< 0.6V), then the transistor remains in the off state
Components Pinout



Conclusion
You can use this street light circuit in places where uninterrupted lighting is required. A lot of bigger projects may harness its capability.
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