Yet another joule thief

Thread Starter


Joined Apr 28, 2012
I've used a 2sc8550 pnp high current.
Now I'm able to light 3 leds in parallel using 2 additional 47uh coils.

The schematic is same as attached.

I'm using this as night light for the ants.

Mod Note: reduced image file size


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Joined Jun 22, 2012
So is it voltage free, cos i cant see the battery on the circuit diagram!! Looks like a modified Colpits oscillator,

Whats the preset do, brightness control...
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Thread Starter


Joined Apr 28, 2012
just another is here

Using a larger 10mH coil but wasnt so easy to get it working + needs fresh battery. With 1W LED tough which has a cooler.
The reflector is needed as antenna for the base.

Ive made the transistor plugable want to test several kinds, started with bc327 which maybe isnt very good for the base antenna variation.
Didnt get any high voltage maybe the primary wire isnt right.

Yes the other doesnt have the battery on schematic.

And yes there are plenty ICs some which I even sell myself.
But Ive learned a lot about transistors made 30 or 40 of these over the years.

No they dont make batteries but sell licenses to put their logo.


ian field

Joined Oct 27, 2012
Didn't know Ford produces batteries...
The local £ store has JCB branded batteries.

IIRC: its a dozen for £1, zinc-carbon, so not really worth any price - highly unlikely to be approved by the firm that makes mechanical diggers.

They also have half-dozen packs of Kodak Extralife alkaline - At the price, they compare with Duracell as long as you don't mind frequent battery changing.

Thread Starter


Joined Apr 28, 2012
The carbons aren't good no
Some years ago I had rechargeable.

I've spent 2 lantern batteries this year and bought lead 12v 18ah

2 10w led chips attached with silicon on discarded pc tower metal plate.

Dcdc converter mosfet from Hong-Kong.
I've turned the voltage down so the plate doesn't heat too much