PCB coil joule thief

Experimental PCB single layer transformer - proof of concept

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This year is Year of PCB coils ;-)
2x 29turns 6/6mil

I know that it is not effective, stupid, expensive, unpractical
but it is great education tool :)

PCB coil joule thief  is certified as open source hardware by the Open Source Hardware Association.

Some boards from first batch are for sale on TINDIE PCB coil joule thief

Mini version is here square-inch-pcb-coil-joule-thief

sch - 409.15 kB - 07/13/2018 at 21:58


brd - 99.88 kB - 07/13/2018 at 21:58


  • 1 × BC546B Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
  • 1 × LED - White Fiber Optics / Emitters
  • 1 × Magic PCB with coil transfomer
  • 1 × Side switch
  • 1 × Battery holder

View all 6 components

View all 7 project logs

  • 1

    Order magic PCB with coil, Eagle boards files are included.
    All other components you can found in your drawer :)

  • 2

    Solder components, Transistor, Resistor, LED, Switch and battery holder, no more components required.

    No wires for transformer coils:), there is all on PCB :)

  • 3

    Insert battery to holder, minimum battery voltage is 0.5V

View all 4 instructions

Enjoy this project?



BillSF9c wrote 08/10/2018 at 18:45 point

Yes, but for edu purposes, think, a 1.5cm ring, die led flashing 1x/sec, small button battery... or, it flashes faster uf your hand is near emf. LED should be green, of course. 😉

  Are you sure? yes | no

Odie wrote 08/01/2018 at 05:35 point

Hi. The new design looks much better than the old one. I'm in a hurry to make a clone . So, do you have a plan to upload the new layout file? 

  Are you sure? yes | no

Sulivvan wrote 07/20/2018 at 15:26 point

Can you post the calculations for the coil, about a year ago i was making joule thiefs and i couldn't get the right calculations for the coil so i just made it by trial and error

  Are you sure? yes | no

K.C. Lee wrote 07/20/2018 at 15:45 point

Eagle CAD has a calculator inside for flat coil. Tools/Calculate Print Inductance

 I hit the menu by accident yesterday.  Also

  Are you sure? yes | no

Sulivvan wrote 07/22/2018 at 10:12 point

Lol i didnt notice , i will try it thank you!

  Are you sure? yes | no

bobricius wrote 07/20/2018 at 19:56 point

no calculation, I just draw biggest possible coil on 5x5cm board :)

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Sulivvan wrote 07/22/2018 at 10:13 point

Dam i wonder if it works on a smaller size

  Are you sure? yes | no

bobricius wrote 07/23/2018 at 09:01 point

I think yes, maybe I try sometime, but everything bigger is better :)

  Are you sure? yes | no

bobricius wrote 09/07/2018 at 21:00 point smaller version also working ... and little better

  Are you sure? yes | no

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