Introduction: Small Joule Thief

Picture of Small Joule Thief

I saw a tiny joule thief here:  I wanted to replicate the size, but leave the application open for use in different projects.  By following this excellent instructable: I was able to fit my circuit inside a 5x5 square of perfboard. It happily powers 3 leds in parallel. 


Radionuclei95 (author)2013-04-22

i just made one in a 3x4 piece of perfboard

bananagirl (author)Radionuclei952013-04-22

That looks awesome!! Makes me want to go even smaller...Where is the resistor though? Underneath the board disqualifies you from competition(!)

Radionuclei95 (author)bananagirl2014-05-18

it is hidden behind the transistor :-)

reopoop (author)2013-08-14

guys i want to makeone of this but i only have C1815,A1510Y transistor.. and dont know the resistor to use because i dont know the color to choose..

Ploopy (author)2013-04-27


absolute zero (author)2013-04-08

This is very neat, very clean looking as well!
I was wondering if you remembered where you got your ferrite bead from. I can't seem to find any. Also, I noticed you have only 5 wraps where most other thiefs use upwards of 20, does that effect the performance at all?

bananagirl (author)absolute zero2013-04-09

Hi! Thank you! I found the tiny ferrite bead inside a Philips "Genie" 11w CFL bulb. The instructable I followed recommended 6-11 turns on the bead, with 11 being the maximum advised. I used the smallest wire available to me and just squeezed 5 turns. It has been running 3 UV leds in parallel for a few nights now from an otherwise dead battery. Everything seems to work OK, but I'm not really sure how to test performance to be honest!

absolute zero (author)bananagirl2013-04-09

Okay, thank you! The only ferrite I have been able to find is much too big, I will continue to scavenge :)

bananagirl (author)2013-04-01

Thank you so much for your very informative and helpful comment! I will be sure to take your advice.

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