Big Joule Theif

[shlodo]

My Joule Thief Experiments

Hi Guys,

Ive been playing around with the Joule Thief circuit myself and just wanted to share some results.

I did an experiment and crunched some numbers to see how efficient this circuit really is.

I found that (in first vid) the setup was over 20 times more efficient than conventional electronics, not considering the fact I was also charging a secondary battery.

I conducted a charging test and here are the results. I was also lighting 2 white LEDs while running the test.

start Charge Run
0 1.5 2.7
5 1.78 2.7
10 1.83 2.69
15 1.85 2.69
20 1.88 2.69
25 1.9 2.69
30 1.91 2.68
35 1.91 2.68
40 1.92 2.68
45 1.93 2.68
50 1.93 2.68
70 2.55 2.66
80 2.55 2.64

Heres the video:

YouTube - Joule Thief Charger - Crunching the Numbers 01


I built a larger Joule Thief that can light 90V neon from 3V. I found that the voltage across E and C turned from negative to positive as I changed the resistance. Also there is a point where the meter reads zero voltage yet the neon still glows. I cant make sense of it, Negative resistance??

YouTube - High Voltage Super Joule Thief Resonating 02

Anyway, just thought Id share this with u guys,

-Shlodo

[sucahyo]

I think you should try swapping the charge and the source part to see if charging voltage really have power not just "surface charging".

[Inquorate]

Dude, I have found negative current draw too

Which I posted in Aromaz thread yesterday..

This circuit needs lots of scrutiny. Will watch your videos tomorrow, off to bed now.

Tnx for sharing
:-)

[slayer007]

Hello Shlodo

Great to see you posting in the forums.
Them are some impressive numbers.

Excellent video's allso.
Please keep up the good work.

[slayer007]

So u had the Thief running into an ignition coil, cool idea. But wat was your amp draw Slayer007??
did the load dictate your draw on the front end?

cheers

The amp draw for the ignition coil was around 30 to 50Ma more.
But it was allso lighting another cfl.

But the cool thing I was able to pull the BEMF off the ignition coil and charge more batterys.

When charging batterys the cfl connected to the JT would go out but the one on the irgition coil would stay .

The batterys I was charging was 10 AA batterys and they charge up rather fast.

There is so many differant things you can do with this circuit.
I'v been having a lot of fun lately.

I allso tried the BEMF Booster thing I did with one of my other projects and was able to light up a 110 night with the BEMF.

It wasn't bright at all but it did light up off one AA battery.

[Inquorate]

Negative voltage

@ shlodo, does the amperage as well as the voltage go negative?

[Xenomorph]

@Slayer007:
How would you integrate the BEMF Booster into the toroid winding concept?
Would you use a bifilar secondary to send the BEMF through the coil again?

[slayer007]

@Slayer007:
How would you integrate the BEMF Booster into the toroid winding concept?
Would you use a bifilar secondary to send the BEMF through the coil again?

No, I was just sending the BEMF from the collector back through the one ac coil.

That way it would have enought current to light a 110v night light.

The ac coil has a lot of voltage but not much current.
It wouldnt light the night light even tho it was around a 1000v.

But sending the bemf that was about 5v back through the coil would raise the dc voltage up to around 170v.
And it would light the light.

It's just a different way to get the voltage down and the current back up.

Like I said I was just having fun try differant way to use this circuit

[Lidmotor]

Inverting a Joule Thief

I'm still waiting to get my Toroid core in the mail so I tried something a little different while I waited. I wrapped a ferrite rod with three windings, modified the JT circuit a little, and turned it into an inverter CFL driver. Worked pretty good. Here is the video:
YouTube - Inverting A Joule Thief

Lidmotor

[slayer007]

very nice Job.

The light looked Very bright allso.

Have you tried it with any less voltage?

[Lidmotor]

More for less?--(More windings same brightness/less voltage required?)

very nice Job.

The light looked Very bright allso.

Have you tried it with any less voltage?

It will light LEDs on a 1.5v AA on the BEMF but not a CFL on the secondary. I got it to light a small flourscent bulb bright at 6v and .5amps. The big bulb in the video took 12v at 1 amp. More windings on the secondary might make the difference. I'm going to save my wire for the windings on the toroid core when I get it. 800 turns should do it. That may take a looooong time to "sew" onto that ring. I'm worried about shorting out between the layers. I have had trouble with that happening on the 'rod' core. You have to insulate each layer to keep it from happening.

Lidmotor

[slayer007]

In between each layer I would put a layer of masking tape.

I'v done this with all my coils I have made,
It makes it easer to wind the next layer and helps insolate.
So they dont short out between layers.

Edit.

Allso you might want to add a second transistor Like in the circuit I did.
That way you can have more power going to the base if you need it.

[Bast333]

Lidmotor's shorts

Another possibility is clear nail polish. Capillary action will help pull it a layer or two down into it and it will hold the wire in place. It does take a couple of minutes to completely dry, but I only can steal a few minutes at a time to work on this stuff. Personally, I like seeing the wires of a well made transformer. Not that any of mine can be called well made.

P.S. Huge fan of yours and others on this forum. I spend much (much) more time reading than posting. Trying to make an effort to give back to that and those from which I have received so much.

[Inquorate]

Nail polish

Thanks for that idea, I've built a coil winder and was going to pump out a few Bifilar coils.. But I guess now they will take a little longer..

'Patience is a virtue, possess it if you can. It is sometimes found in women, but never in a man' - Peter Strelein (my grandfather)

[Lidmotor]

Got my 2" Toroid core today----Tomorrow I 'sew' it

Thanks for the tip about the nail polish. Someone else recommened teflon tape and I tried that today and it worked great. I got the Toroid core today and will start wrapping it tomorrow. Also today I had another go at the 'Inverted Joule Thief' and wound 200 more turns on the secondary. Better perfomance with more light and better charging.
Here is the video:

YouTube - Inverted Joule Thief Part 2

Lidmotor