Picture of LED Torch
Simple steps to convert your old bulb torch to LED Torch for just 1 $
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Step 1: Step 1 - Parts & Tools

Picture of Step 1 - Parts & Tools
1.Power LED 1 Watt  with heat sink  - 1 No  -------------->                                                   10  Rupees
2.Resistance 10 Ohm  1 watt or 4.7 ohm 1 watt for more brightness - 1 No.  ----->       1
3.Switch SPST  - 1 No.                                                                                                                 5

4.Diode  IN 4007 - 1 No.                                                                                                              2
5.Resistance  1k - 1 No.                                                                                                              1
6.LED Red - 1 No.                                                                                                                         1
7.Charger socket (Audio )                                                                                                            5
8.Battery  4V  0.4 Ah (SMF)                                                                                                         35
                                                                                                                             Total            ---------------  60  =    1 U.S. $

Charger you can use any old existing charger which is rating 5 Volts  or can use mobile charger also for this you need to change the socket accordingly.

 Note : If you want  to have long duration  , you can change battery 0.4 Ah to 1 Ah which will fit in the torch, the price is around 50 rupees in India.

Step 2: Step 2 - Circuit Diagram

Picture of Step 2 - Circuit Diagram
Here is simple circuit diagram and , ray diagram of torch just to help assembling parts.

Step 3: Step 3 - Assembling

Picture of Step 3 - Assembling
Before start assembling  first you remove bulb , slide switch from the torch.

Make 6/5 mm hole for charging socket and 3 mm hole for red LED as shown in picture. cut the square hole for switch as required.

Make wiring as per circuit diagram, just see the photograph.

After completion of  wiring do the continuity test & charging voltage , if all test are done then switch on torch , here you go live.

Step 4: Step 4 - Finishing

Picture of Step 4 - Finishing
Finished torch, see charging indicator. Here we go live.
vr_aryan9 months ago

Hi Mr. Mahadev,

I saw you simple LED rechargeable torch project and I am excited. Well I am not an Electronics Professional or a graduate but I am quite interested in Electronics. Anyways I have a few clarification to make I..e 1. What could be back up do we get if we use 1watt LED.

2. can we use 3 watt LED with a battery with higher capacity(Ah) to get better back up?

3. what if we build the Charger Circuit inside the Torch instead of having Charger separate? With that we can connect the torch to the mains directly.

4. what do u think about transformer less charging Circuit in respect of durability and Safety?

I request you to clarify my doubts and need you help. Awaiting for your reply.

Vinay Rao

Mangalore, Karnataka State

Email ID

vprasad1 year ago
Dear Sir
its really nice, & where did you purchased power led for 10rupees pls send the address of shop
elect design engg
mahadevrm (author)  vprasad1 year ago
Hi vprasad i dont which city u stay, i generally purchase in Hyderabad Koti area or bangalore SP road, or Mumbai Lamington road you can buy from any electronics shops.

saw ur project its very simple and unique me from mumbai ...

vprasad1 year ago
Hi sir
I am in Coimbatore Tamil Nadu
here i searched 3W3.5VDC its cost of 90rupees
mahadevrm (author)  vprasad1 year ago
Hi i think price is high , it should be around 30-50 max, and more important is 3Watt LED exhaust battery very fast so my suggestion is alternate to this u can use general LEDs 5 nos solder very closely u will get nearest brightness . i have uploaded new image for your reference. u can reach me for any help.