The circuit diagram of Automatic head lights turn off circuit has been explained here. This circuit can be installed in a car so that it will automatically turns off the head light after a certain time after ignition switch has been turned off. The time duration for which the light should burn can be set by the end user. If this particular circuit is used in a car, the user can walk out easily from the dark garage in the light from head lamp of the car.
NE 555 timer IC is the heart of this circuit. The voltage from battery is fed to the relay through diode D1 when the ignition is switched on. It produces a negative pulse at the pin2 of timer IC when ignition is switched off. Then the output of timer becomes high for a certain time determined by resistor R1. This triggers the transistor Q1 into conduction and relay is energized and that drives the head light. When the preset time exceeds, the head light goes off.
- Use a good quality PCB or common board to assemble this circuit.
- User can easily set the timing by fitting the potentiometer on somewhere on the dashboard of the car.
- With the value of components used you can make a setting from 10 S to 60 S.