High Voltage Joule Thief!





Introduction: High Voltage Joule Thief!

this is how to make a high voltage joule thief!
the ones i made were 90 and 180v but the more
hv turns you do the higher the voltage(about 1v per turn)
this circuit runs best @2.4v-3v

Step 1: Materials.

you will need:
toroid core(ferrite)
2n3904(sometimes others work too)
512ohom resistor
winding wire(0.15mm approx)
0.2-4mm as well!
neon glow lamp (i used maplin rx70)

Step 2: Wind the Hv Windings.

Get your 0.15mm wire and wind at least 85 turns
through the middle of your toroid like the pic.

Step 3: Wind the Low Voltage Windings.

twist the high voltage wires together to make winding easier
using your 0.2mm wire wind 5 turns and make a center tap
and then wind another 5 the center tap is the positive 2.4v.

Step 4: Put Together All the Parts.

now put all your parts together .
and test it!



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80 Discussions

I came to this publication via another youtube video by this author. There You can watch a demonstration of this gismo and the purpose for what it was intended . This dummed down version is pretty much useless.

1 reply

I was sorting through some electronics - and found this circuit again - I could never get it to work..... I had another go this year- 5 Yrs on and still nothing..... being pragmatic and very analytical- I felt the 1amp 2222 transistor, it was very hot -!I tried everything but then I noticed if you flick it on and off there was life -(not oscillating) . I re- wound the primary in thinner wire and in 1 direction not [S] Orientated or bucking and it finally worked!!!

It's a good circuit it's kind of a variant of a slayer exciter - or Tesla HF switched pwr supply ...sweet..........

Yes it should, the ferrite creates a good path for the magnetic field, which is setup by the inductor.

Can someone please answer my question I wound the high voltage winding all around the toroid will that work if I wind the primary over the secondary high voltage winding.

Voltage divided by resistance gives you the current.

You don't really know what resistance is going to hang on to those HV terminals of 450 volt. And those capacitors pack enough juice to make you see stars.

But still, adding a fuse defeats the whole purpose, which is giving something a jolt.

well. you are wrong. 2N3904 can handle max 200mA. So 2.4*0.2=0.48W (U*I=W). And i don't know from where you took that 450v. author said:

,,the ones i made were 90 and 180v''.

Let's use formula:(I=P/U)

0.48W/450V≈0.001A 1mA

0.48W/180V≈0.003A 3mA

According to http://yagitech.blogspot.lt/2011/10/electrical-ha...

1mA trough body not noticeable

1-3mA trough body is mild sensation, not painful

Actually, those transistors will charge capacitors at a rate of milli amps, but the discharge rate of the capacitors are not restricted.

(using your logic)... If i charge capacitor with 2mA, i instantly can get 200A out of it :D? To charge bigger capacitor you will need A LOT of time...

If you will want to argue more, then build this circuit, measure output current and then you can say something. Theories without facts are nothing!

There are no capacitors mentioned in this instructable. (your imagination created 450v and capacitors:) )

This is a perfectly good circuit, but you don't actually need 2 coils.

If you use the original joule thief design, add more turns of thinner wire, and choose a good value for the resistor, you can get the same voltage range. This way you save yourself a little work and wire.

Quite by accident, I got a standard joule thief to produce 100v from a 1.5v cell with about 50 turns of wire, a 2N2222, and a 500ohm resistor. More turns of wire should increase the output voltage.

To those getting 0v output: you probably connected the wrong ends of the coil together. If you were to connect the "start" of one wire to the "end" of the other, that would be correct. Otherwise, your transistor won't oscillate and you get no output.

The usual precautions for working with higher voltages apply.

4 replies

That's actually a bad idea. it exposes the transistor to the high voltage output which will kill it after a while. its better to build it this way and put a varistor on the output to prevent it from getting burned out if you turn it on without a load.

can you post the specifics and schematics for you 100v joule thief? it sounds very cool. an ible would be great!

I did five layers of 60turns ,that s 300turns right??, but I only get 34v 1a

Hello... Im really in need for your help! I didnt know how did you wrap the wires around the toroid and how did u connext them in the circuit ? please help


2 years ago

How about putting the number of turns clearly on your schematic........ Please !

Nice! Joule Ringers are interesting little circuits. I use one when I need > 30 volts for finding negative pins on fly back transformers.

For some reason I can't get mines to work, I measured the voltage it was out of range on my multimeter set it to AC, but it doesn't light up an neon or so. It lits up a LED without a sweat. The parts I use is a toroid core, 85 turns of HV, 10 turns on the LV 1 and 5 turns on LV 2, NPN 2n3904 transistor, 500 ohm parallel resistor. I've tried 5 turns on the LV 1, but it doesn't seem to work. I use 2.4 volt as an power supply.