Street lights projects in simple way

Street lights are very useful devices, It provide light automatically during night. Street LED lights uses LEDs instead of Incandescent lamps. Here is the simple circuit for street lightning. Solar street light is the advanced version of the ordinary street light.

Components

1. Rectifier (Step Down Transformer, Diodes-4, Capacitor-470μF)
2. LDR (Light Depended Resistor)
3. Resistors (56KΩ,100Ω)
4. Transistor BC187 (2)
5. 6V or 12V Relay
6. Bulb

Working

• The bulb is Off during day time and it turns on automatically during 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 are created a potential divider with 1 arm is ordinary resistor and other arm is 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 is 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 turns on then the relay coil energizes and the bulb will glow

• In the Light, the drop is very small (< 0.6V), then the transistor remain in off state

Datasheets

1. 1N4001-1N4007

Components Pinout

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