Big Joule Theif

[ApEkV2]

problem again

I can't get this one joule thief circuit working, and the other three are working fine.

larger toroid.jpg

I have the same number of wraps as my other toroid, but the only difference is I'm using a to126 package transistor instead of a 2n2222 and the toroid is larger than the other one. The to126 package transistor works fine on my others as well. The green coil is for later tests, and the yellow thing in the toroid is a new ear plug to keep the wires in shape.
The potentiometer is a 22k in series with a 470 ohm resistor. Could someone help me out again?

Matt

[Inquorate]

Sure you've got the right wires?

Or they could be shorted out somewhere. Put a lightbulb in series with battery and coil to make sure the right ones are contiguous, then try another lightbulb to battery and contact the other wires to see if it's shorted. That's all I can think of.

[ApEkV2]

Yes that checks out, there are no shorts in the circuit. I still can't get the toroid one working.
Maybe I need more turns on the toroid.
I tried base resistance values from 470 ohm to 22k using a potentiometer.

This one works better than the others that I made.
I found out that shortening the length of all the leads makes a small difference on the operating frequency.

Finished JT.jpg

[sucahyo]

Either the duty cycle is too short or the frequency is too high but I can' get any kind of useful spark even though the 3055 is getting pretty hot.

just FYI if anyone tries this, check your transistor on the camera board. Mine was a D2470 and the pin outs are E C B. I've got a 100ohm resistor at the Base of the 2n3055 triggered by the collector (center pin) from the D2470.

I found different transistor brand have different BEMF. Try Toshiba.

Is it hot because the current is too high or BEMF is too high? Have you use any resistor between the power source to transistor collector or emitor?

See if there are BEMF voltage between collector to power source. Place a diode directing to power source and measure amp or voltage.

I can't get this one joule thief circuit working, and the other three are working fine.

If the transistor not dead try using lower resistance. I use 100 ohm as minimum which is always work.

How about changing your wound? wound the wire side by side, avoid twisting, covering the whole toroid.



Here is a comparison of three air coil
YouTube - Joule thief BEMF comparison 2, plus moebius coil

Moebius coil is easier to make than flat spiral coil. Anyone ever use them before?

[slayer007]

I found different transistor brand have different BEMF. Try Toshiba.

Is it hot because the current is too high or BEMF is too high? Have you use any resistor between the power source to transistor collector or emitor?

See if there are BEMF voltage between collector to power source. Place a diode directing to power source and measure amp or voltage.


If the transistor not dead try using lower resistance. I use 100 ohm as minimum which is always work.

How about changing your wound? wound the wire side by side, avoid twisting, covering the whole toroid.



Here is a comparison of three air coil
YouTube - Joule thief BEMF comparison 2, plus moebius coil

Moebius coil is easier to make than flat spiral coil. Anyone ever use them before?

Thanks for posting that video Nice Job.

I was thinking about using a Moebius coil for my next JT.
I would like to wrap some thin magnet wire on the outside of that and see what happens.

Edit.

Hers a link to how to wind a Moebius coil.
I'd like to use this in my next JT and try wraping some thin magnet wire around the outside of it and see what I can pick up.

http://www.littlemountainsmudge.com/howto4pulsersample.pdf

[Inquorate]

@ slayer007

Is this a 'correct' joule thief circuit? It burns up potentiometers after running a couple of seconds, and coil starts screaming.

[Inquorate]

Oops, link

purple+flasher.jpg (image)

[slayer007]

Is this a 'correct' joule thief circuit? It burns up potentiometers after running a couple of seconds, and coil starts screaming.

Yes its just a basic joule thief circuit.
But you need a big coil to run it with 12v or your transistor will fry.

You could allso try it without the pot.
I dont use one in mine,but it is nice to controll the voltage.

[ApEkV2]

I found that small switching diodes and zener diodes (only tried 12v zener so far) work in place of the 1k resistor.
They gave me different results, but the LED lit up brighter. I still can't get that stupid toroid to work though.

Here is my video showing that a zener diode works in place of the resistor.

YouTube - Joule thief #1

[Lidmotor]

Lazy Joule Thief

I found that small switching diodes and zener diodes (only tried 12v zener so far) work in place of the 1k resistor.
They gave me different results, but the LED lit up brighter. I still can't get that stupid toroid to work though.

Matt---I made a joule thief yesterday that didn't work. At least it didn't want to work. I finally poked at it enough and it finally did it's job but not well. I tried a standard 1/4 X 20 lock nut as the core and wrapped about 40 turns of twisted wire on it just to see if that would work. It just sat there. I thought that it might be my other circuit components so I swapped out the coil with my big trifilar that I used in the 'Big Joule Thief'. Everything was ok and the circuit ran fine. Soooo-- I got mad. The thing should have worked if the theory about WHY it works was correct. I started trying different transistors, resistors and LEDs----the shot gun approach. Just fire a bunch of stuff at it and force it to work!! It finally did but the amp draw was higher than if should be and I fried two transistors. I really don't know why it started working. Sucahyo's ideas are good ones about what to do to get it running. In my case I think that twisting the wires was a mistake and the iron core needed to pickup some kind of field before it would start up. Also I was using clip leads on the long ends of the coil wire. You are right I think that the coil leads should be short and firmly attached somehow. If all else fails, just build another one. About 30% of what I build never works.

[sucahyo]

battery charging

Hers a link to how to wind a Moebius coil.
I'd like to use this in my next JT and try wraping some thin magnet wire around the outside of it and see what I can pick up.

Actually, mine is a lot more primitive. I wound the bifilar over it self in 45 degree angle after one loop.


@all, I use 1 Amp transformer for my 12V joule thief.

I wonder which one is more effective for charging battery. PNP or NPN?

[slayer007]

Here is a video of a small joule thief with a secondary coil winding.
The second coil puts out about 8 volts and can fill a large 4400 mfd capacitor to over 75v in about 10 minutes.

It will allso charge 10AA rechargable all at once just on the second coil.

This is running off a rechargable 1.2v AA battery that has 1.28v in it.
It took about 10 minutes to recharge 10 AA batterys from 8.9v to 13v.

YouTube - Joule Thief With Secondary Coil Winding


EDIT.

I let it run for about an hour longer to see how high it would go up to.
The charge batters went up to 13.22 and the run battery went down to 1.26
Then after letting set for two hours the charge batters settled to 12.50 and the run battery went back up to 1.28 where it started.

[redeagle]

Has anyone been able to test the joule thief against the bedini style solid state oscillator for a comparison between input and putput current?

Matt

[sucahyo]

Has anyone been able to test the joule thief against the bedini style solid state oscillator for a comparison between input and putput current?

Matt

I don't have Bedini SSG, I only have joule thief.

At 12V 0.25 Amp input, it charge 12V battery at 0.11Amp. When the charge battery removed, the input current reduce to 0.22 Amp. I guess 0.22Amp is consumed for powering the coil and heating it. Should be more efficient at higher Amp (longer coil and reduced coil resistance) Joule thief using Toshiba 2N3055.

Edit:
Anyone ever parallel additional transistor? It draw more current but the BEMF also increase too. Just playing with two TIP2955, single = 0.23A, double = 0.27A. I don't monitor the BEMF amp, but I use it to drive an ordinary computer fan. The fan speed is higher when I use double.

What I mean by parallel is two transistor or more joined together, collector is binded together, emittor is binded together, base is binded together.

Here is what I mean:
Max BEMX is not at max input current draw

[slayer007]

I don't have Bedini SSG, I only have joule thief.

At 12V 0.25 Amp input, it charge 12V battery at 0.11Amp. When the charge battery removed, the input current reduce to 0.22 Amp. I guess 0.22Amp is consumed for powering the coil and heating it. Should be more efficient at higher Amp (longer coil and reduced coil resistance) Joule thief using Toshiba 2N3055.

Edit:
Anyone ever parallel additional transistor? It draw more current but the BEMF also increase too. Just playing with two TIP2955, single = 0.23A, double = 0.27A. I don't monitor the BEMF amp, but I use it to drive an ordinary computer fan. The fan speed is higher when I use double.

What I mean by parallel is two transistor or more joined together, collector is binded together, emittor is binded together, base is binded together.

Here is what I mean:
Max BEMX is not at max input current draw

Yes I'v done the same with the pulse generator I was working on.
It was like the more transistors added the less power it used and the more it would put out.

If your transistors get hot this is allso a good way to cool them off a bit.
Adding more transistors splits the power between them so theres not so much power going into just one.