Automatic Emergency Light Circuit

How to make an Automatic Emergency Light Circuit for simple home uses using led lights.

By:Alok kumar

Today we are going to learn how to make a Automatic Emergency light circuit or Electronic candlefor simple home Power failure situations. Most of the time when unexpectedly power failure occurs suddenly we require a Light dource to see things in the room. For this purpose we are going to make an Efficient Emergency Light which Automatically turns-ON when power failure occurs.

Components Required:

Any Charger suitable for your battery, or 220V to 4.5V / 600mA Transformer D1 = 1N4004D2 = 1N4001R1 = 33Ω/1WattR2 = 470ΩC1 = 470µF/16VT1 = 2SB242 ( This is a pnp type transistor)LED's = Buy 4v led's( 8) Battery = Li-ion 4.5v 4AH or any battery either it is 12v or 6v but you need the good Charger for that battery in my case and also Increase the rating of diodes.


LED's According to battery specification or arrengement of led. In my case i use Eight good LED in parallel connection .

Circuit Diagram or Schematics of Automatic Emergency Light:

Automatic Emergency Light Circuit or Schematics

Working of Above Automatic battery charger circuit:

So here in this circuit the charger i have selected a 220V to 4.5V / 600mA Transformer but you can selected any charger according to your battery specification for e.g. if you are selecting a Li-ion battery 4.5v 2AH Then choose 6v/ 600-800mA CHARGER raidely available (cell phones charger).


So here the main role is played by the PNP type transistor T1 = 2SB242.


The Voltage from the battery charger is rectified by Diode D1 and it is also filtered by capacitor C1.The Li-ion Battery gets charged by the current from charger via the diode D2 and Redidtor R1.

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Here when the main power failure occurs then the charging current is interrupted or stoped then a current flows from the base of transistor T1 through the resistor R2, Which actually trigers the Transistor to conduct and our LED's start glowing.






Case 2, When main power returns we want the Emergency Light to switch-OFF. Now when the main power returns a charging current flown to the battery via D2 and the transistor stop conducting and our LED'S stop glowing.






Make this Marvel piece of GADGET( Electronic Candle or Automatic Emergency Light using LED'S.) and enjoy and forgot conventional candle and enjoy.


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