Big Joule Theif

[Inquorate]

Oops, link

purple+flasher.jpg (image)

[Inquorate]

@ slayer007

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

[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

[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?

[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.

[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]

problem again

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



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

[Mutten]

Shamelessly borrowed from OU.com but I went with the disposable camera circuit for a quick and dirty method of playing around with the JT.

I wanted to see if I could get the circuit to trigger the base of a 2n3055 backed by a 12v SLA to power my tesla coil.

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.


Ignore the top half of the breadboard, that's just my 555 driver circuit I've been playing with, its disconnected in this pic.

stack of pennys are just a heatsink. I've found they help and they sit nicely on the top of the 3055.

http://i197.photobucket.com/albums/aa23/muttenmagroo/tesla.jpg

[slayer007]

Here is a video of a little joule theif with a transformer attached to it.
You can allso add more coils or transformers to it.

This can allso be done with the big joule theif.

YouTube - Joule Theif & Transformer

[sucahyo]

@Inquorate, I also got purple light on my cfl. That is the sign of high BEMF. When the BEMF is high, the CFL show some slight purple color.

Here is the video:
YouTube - Purple ligth shown when BEMF is high


@Mutten, I think you can use your tesla coil too. My circuit with tesla bifilar flat spiral coil produce more bemf than the one with tubular air core coil.

[Inquorate]

Can't edit my posts, sorry

Reposted videos to youtube, here's updated links

YouTube - Inquorate 24 - slayer's big joule thief

http://ca.youtube.com/watch?v=NGGd9tJGx0c

YouTube - brighter purple flashes

[Inquorate]

Video doesn't really capture the brilliance

In the video you can only see the light reflecting on the carpet, but in real life the globe goes super purple. Worth fiddling with till you see it :-)

Oh and I believe it happens when switch on off is super quick, once orange glow shows up contact is too long.

[Inquorate]

Video doesn't really capture the brilliance

In the video you can only see the light reflecting on the carpet, but in real life the globe goes super purple. Worth fiddling with till you see it :-)

[Mutten]

After I get settled in I am going to build a mini JT and see if I can get it to trigger a 2n3055 to pulse my ignition coil backed by a 12v SLA. I'm still messing around with my tesla coil and I want bigger sparks

After I saw Lidmotors scop shots last night, it might work.

Also picked up some disposable camera housings from CVS. They gave me a handful of them for free. Was reading on OU forum people were modifying them to get the same effect. Made it to page 98 last night with some heavy skimming.

[Inquorate]

Orange neon flashing purple with big julie circuit

Just thought I'd share this, effect hard but not impossible to reproduce, all the contacts have to be clean and gotta move the clip where it is on the neon.

But in effect, this system behaves differently at switch on than when running.

I'd love to see the waveform of purple flash moment on an Oscilloscope.. :-)

Setup
YouTube - Inquorate 24 - slayer's big joule thief

Effect
YouTube - Inquorate 25