Picture of high voltage joule thief!
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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)
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For Safety procedure Try to Put Fuse in HV LEad

:D really? hv output is very, very low current so it can't blow fuse

eyal_hadar made it!8 months ago

is that the same?



מצלמה ישנה 038.JPG
imakethings6 years ago
what is the output voltage?

Mine is 100v can shock Human

Step 1 "the ones i made were 90 and 180v but the more hv turns you do the higher the voltage(about 1v per turn)"

Try to Short Circuit hahahaha

cool (y)

legionlabs2 years ago
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.

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.

Quite correct! Still quite fun for a 0.07$ transistor though!

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

Effluxmind1 year ago
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.
baven3 years ago
Hello there i got problem with this circuit. I got exactly same setting as you with same turn ratio same resistor and transistor and voltage too but when i insert the batterys i get no voltage on the hv output. Any suggestions where could be the problem ?
Hello, have hit the very frustrated stage?? Have built a tiny 8t Bi-fil version which worked fine -same transistor as in your set up......I have since made your version and have had no luck-only that the transistor starts to head gradually.....I'Ve used [2] different ferrite's and thicker wire----?????????? Anyone have any suggestions

:-Have done some research as some ferrites have low or high Hysteresis -understanding that some saturate with magnetic field and some enhance field strength /Flow.....?
NatureTM3 years ago
Thanks for the example. Multimeter shows 500V, however not enough current to light the neon bulbs I have on hand. Skin test doesn't produce a shock feeling either. I'm going to school for CE and just finished my "circuits" class. Armed with my incredibly basic knowledge, I would guess this power supply has an extremely 'high internal resistance.'
wateenali3 years ago
hi there thanks for this great tutorial.I made this circuit and it generates high voltage but the current is too low and it unable to lightup the led bright i cant understand i check the voltage on the meter and it is more than 500v.Please help to solve this problem.
thers no current the thin your hooking it to drops it drasticly giving 3-6 v off
raja264 years ago
I have tried with a thick wire for high voltage output and a much thicker wire for low voltage input.. It works very well.. I didn't connect a resistor though, it can run two 3V LEDs with a single AAA of 1.2V..

The only problem I've got is the heat that builds up in the transistor(2N5294). My another doubt is, whether we could modify the setup to run a dc motor, like simple rectifiers or something.. Thanks for the great instructable. Been searching for a guide to increase DC voltage.
Alex1M6 raja264 years ago
Adding a resistor to the base might help with lowering the amount of heat the transistor produces.
raja26 Alex1M64 years ago
Hi Alex, Thanks for replying. I have figured it out by myself. But can you just tell me how I can run a DC motor with it.
Alex1M6 raja264 years ago
Could you try placing the motor in place of the LED? If it does not run use a 3v input with two AA battery's in series.
raja26 Alex1M64 years ago
Thats not possible, because the motor runs with just the battery itself, so when using the Joule thief setup it should be working normally. But the output from joule thief is a pulsated DC. I have to convert it to pure DC for making it work. I just want to know what type of capacitor and inductance to use it as a filter for the DC output.
Alex1M6 raja264 years ago
Oh, in that case you might want to try adding a capacitor across the motor terminals. Try different values and see what results you get.
I believe a simple ceramic disk capacitor will do.
Thanks for the relpy Robot Lover. I'm a zero in electronics, so I don't know about these ceramic capacitors and all. All I can do is try some Random Capacitors.
Alex1M6 raja263 years ago
Hi, Sorry about my comment. I just assumed you had electrical knowledge, I tend to do that sometimes with people.

Have a look at the image I have attached it will show you a ceramic capacitor in parallel with the motor and give you an idea of what to look for.
raja26 Alex1M63 years ago
Wow, thanks for this quick help.. By the way, what will be is capacitance?.. This is a fair picture.. Much needed help indeed..
raja26 Alex1M64 years ago
Yeah, thats what I'm looking for but is capacitor alone is enough? Don't we need inductance?. I don't know much about capacitors so please specify some value for that one 1.2 V AAA battery.
PKM6 years ago
Do you know what the waveform of the output looks like? Are the edges sharp enough to drive something like an ignition coil? I'm thinking of something like this- battery powered Jacob's ladder FTW :)
12V (author)  PKM6 years ago
the first picture is when under no load and the second is with a neon wire ended lamp.
iiiiiiiiiiiiiii 002.jpgiiiiiiiiiiiiiii 001.jpg
ramatern 12V3 years ago
OK, now I'm interested. What I'm looking at is a sine wave. Why can't I get an inverter to give me a nice sine wave like that? Can I adapt this to function as an inverter? ;-)
PKM 12V6 years ago
Awesome, O-scope traces- I was half expecting a response along the lines of "WTF are waveform edges" or "no" or something. Still, that looks like a "no" because it's near sinusoidal with a load on it. Oh well.
Xellers PKM6 years ago
555 timer
12V (author)  PKM6 years ago
i do know of another circuit that is a load of dc pulses
but i haven't got o-scope traces because mine broke so i have to make another circuit.
when i made a circuit i will take more o-scope pics.
Adam Manick PKM4 years ago
That is not battery powered. You plug it in. And yes you can get nice arcs from this circuit with a little improvement.
NcssR4 years ago
hey guys,at this joule thief works a c945 or bd 139 or sdt9208 power transistors
Mudbud4 years ago
I can not find a 512ohm resistor anywhere! what else can I subsitute?

P.S no Im not going to get one online, I'm not old enough. :)
sdobbie4 years ago
Would an n channel enhancement mosfet work instead of the transistor. I have a p60nfo6 mosfet and a k3567 mosfet.
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