Jan 1, 2013


Automatic LED Emergency Light

NOTE: Considering the doubts raised by many of our valuable readers in our Comments section, this circuit has been modified by Mr.Seetharaman, one of our valuable contributors. You can see his modified circuit here: Automatic LED Emergency Light Modified.


This is the circuit diagram of a low cost emergency light based on white LED.The white LED provide very bright light which turns on when the mains supply is not there.The circuit has an automatic charger which stops charging when the battery is fully charged.
The IC LM 317 produces a regulated 7 V for the charging of Battery.Transistor BD 140 drives the out put.Transistor BC 548 and Zener diode controls the charging of the battery.


It is always better to connect a heat sink with BD 140.Before using the circuit out put of LM317 must be set to 7V by adjusting the potentiometer.

Automatic LED Emergency Circuit Diagram:


Note: R3 to R14 are all 100 ohms

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