Flashlight With Joule Thief




Introduction: Flashlight With Joule Thief

About: Hobbyist and MSX computer lover.

This is probably the 1001 flashlight with a joule thief, but then again this is mine :)
I used a pen style flashlight from duracell.
It has a 2.2 volt lamp and two AAA batteries.
One of the penlites is going to be replaced by the joule thief.
And of course the lamp is being replaced by a 5 mm white LED.
Thanks to all the great ideas on instructables to make this my first instructable.

Step 1: Schematic

The schematic I used for my JT.
I is almost the same as https://www.instructables.com/id/Joule-Thief-LED-Night-Light/
The instructable from ledartist what inspired me to make a flashlight joule thief.
On the second photo is the prototype I made to replace a battery and the lamp.

Step 2: Oops

I made my replacement for the battery a little to short so there was a gap between the battery and the switch.
The solution was a M3 bolt an mutter inside a rubber ring to fill up the gap.
But the best thing to do is to make your print a bit longer :)

The finished led light could last as long as 13 plus hours ..... I didn't see when it went out.
Hope you enjoyed my first instructable.


Emil Sokolowski

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    8 years ago

    This is neat! I have a similar idea for my flashlight, but it has to be smaller to fit inside of a AAA battery slot, hopefully your schematic will help, thankyou!


    Reply 8 years ago on Introduction

    Great you like it, but this design is for a AAA battery slot, or do you mean that you want to use it in a flashlight with only 1 AAA battery. That would be a tight fit. But maybe with smd components you could make it as large as the light bulb ?

    Anyway good luck and post your Instructable :)