Joule Thief

[jeanna]

currently im playing with 2 electrodes outside for a earth battery that is generating 0.8v at 3mah now i thought this would be sufficient to even partially light the joule thief im working with but apparently im not using the right configuration because im unable to get it to work. ill have to tweak it. im going to try and see how far i can push these ground electrodes just for giggles
...

Hi AK,
You are pretty much at the keel over place for even a joule thief. My batteries are pronounced dead by most things at less than 1.2  With a joule thief I can only see the smallest speck of light at 0.85v. (I think, it has been so long since I have used the BJT place for the light...)

First, I would suggest that you take that joule thief and tonight overnight run a AAA battery completely down with it and measure what the battery voltage is in the morning or when the light is out. That should tell you the low end for your set up.

What is your transistor?  2N3904 and 2N2222, are fast but gadget has some germanium kind which turns on a 0.3V. The more switches the more the jt works so the quickest changer at the lowest input volts wins.

The uneven primary with usually 2-3 turns going to the base and 2-5 turns to the collector is often better than any more. (it depends on the ferrite toroid here)  This gives the transformer action of the secondary a greater advantage or a greater output voltage per secondary turn.

Are you using a cap in parallel with the EB leads? That is probably essential, at least where the EB volts are low. (remember Bill's picture of the led on the tree stump? that was with a supercap in parallel.


@xee,
Thank you for all that information. And-that interesting bit about the neon only glowing at one side.
I was playing around with it today and noticed that it will turn on with only one secondary lead under certain circumstances.

I am not sure of all of them, sometimes all I seem to need is to have the other lead pointing toward the neon and other times that does not work.

I can reliably get it to light with one lead if I am holding the other lead and touch my hand with the free lead. It must be using skin effect to connect.
The other time it lit was when I clipped the one lead and not the other lead but touched the lamp glass then either held the secondary near my hand that was touching the glass or when that wasn't enough touched that secondary lead to my skin.

One time and I think it was the last example, I thought both leads went on, but it is hard to see at some angles. I still have left the 33kohm resistor in there. It is amazing that this with the 33k ohm resistor lights fine, but the fuji cam neons don't.

@Altrez, welcome back.
Me either. I got 475volts today and no fluoro tube. I think Ms destructo needs to come over again and take apart a little cfl, maybe they are easier to start...

jeanna

[gadgetmall]

Just got a batch of new TOPHAT flood leds . 115kmcd / Here is My light amplifier . Its a chunk acrylic .9 X16 inches the first one is with one led stuck in a hole drilled and the second is the other side with another tophat . Its Bright and can be a tabletop Light . Two leds and lights Up very bright . Its amazing how acrylic carries the light to every corner
Gadget

[gadgetmall]

Hey pirate why did the pics show up as attachments ??
Gadget

[jeanna]

@AK,
If what you say is true about the neons showing ac when both sides light then the hand held thing is ac. I just checked it and it lights both sides when I clip it and touch the glass.

Sometimes the light stays lit when I drop the wire and it seems I only need to touch my hand once and the charge will continue until I let go. How cool is this!

But I am not sure about the ac. I touched the glass on only one side and that one side lit then moved to the other and only that side lit.

@Gadget. I only get a notice from the site that an error has occurred when I poke your new acrylic tophat pics.

jeanna

[gadgetmall]

@AK,
If what you say is true about the neons showing ac when both sides light then the hand held thing is ac. I just checked it and it lights both sides when I clip it and touch the glass.

Sometimes the light stays lit when I drop the wire and it seems I only need to touch my hand once and the charge will continue until I let go. How cool is this!

But I am not sure about the ac. I touched the glass on only one side and that one side lit then moved to the other and only that side lit.

@Gadget. I only get a notice from the site that an error has occurred when I poke your new acrylic tophat pics.

jeanna

Yes i just looked back at all our picture and they are all attachments now . no pics . just links  Is anybody else having the same problem seeing pictures posted  ?