Joule Thief

[altrez]

Well I have had a rash of toroids that do absolutely nothing. I can get them to work sometimes but this is too much. I spent way too much on these chokes to have them refuse to turn the transistor on.
@All... help!!!

@Altrez HELP!!!!

I bought 2 small ones of this u=60 and u=125 because they are the same outer dimension as the filter I like so much. I wanted to compare things with the same size and number of turns.

I started with 5 of each for the bifilar primary and this won't even turn on the light. the transistor gets hot and nothing happens.

It means to me there is no turn-on of the transistor but why would that be?
The biggo did the very same thing.

My question to you is how many turns do you use on your primary. Have you found that it takes more than the others you have used?

thanks,

jeanna

Hey! It takes more turns on the big ones try a 12/12 and work back from there. PLEASE let me know if you have any more problems.

-Altrez

[altrez]

OK here is what helps.

Now I understand those among us who seem to always have the 104k cap in parallel to the base resistor.

I wound another primary and got the BJTL to go on with
4TB,11TC,(I have a temporary pickup of 10 turns.)

So, the toroid needs 4T,11T to turn on the led and have it be bright enough. I started to remove some of the 11T from the collector coil and the amps draw started up and the light got dimmer. egads! I started with 11T of each and went down; maybe I should add more than 11 to the collector coil.

The 10T pickup is producing 2.12V but ONLY if I have the 104k cap parallel to the base resistor and the light is in there.
If I pull out the BJTLed, the volts off the secondary go DOWN to 1.8v !!

The frequency is 1.4MHz

I guess I got my high frequency. 

jeanna

Hey Did you test with the scope on the pickup coil to get that reading? of 1.4MHz? I have been seeing the same thing on my large Toroids. Yes you need a 12/12 to get started with.

I am having some trouble understanding how to add the cap to the JT. When I don't have it I spike to 400v when I do its less then 10 v? Where and how should the cap be placed?

Thanks

-Altrez

[resonanceman]

@All

Problems with slow connections and Videos
Gary I know exactly where you are coming from, I still have slow dialup.

Gary, to make my part more enjoyable here I make a small videos with my mobile phone, I put it to the smallest 640x??? image it can go, then make a video, but I have to stop recording the file when it size gets to about 240kb. So 12seconds is my limit.
This is because Stefan has only alowed 250 Kb as an image file Max size.
To post the video file, I click on the Browse button, tell it to go fetch and click on the post button.

I also find it difficult to download these big video files from YouTube, so this was my way to help those who have slow download speeds.

Hope this helped you

jim

Jim

You must be talking about those teeny weeny videos
I have seen  them but never got one to play .

Does it  require a special player ?


gary

[jeanna]

Yes, I use multi layer coils. Added layers are about the same as original. I thought maybe you were working on your large toroid. I find it hard to get a lot of turns on small toroids.

Increasing permeability increases inductance per turn. Thus it takes fewer turns with high permeability to equal the number of turns in a low permeability coil. In general it is best to have high permeability but also in general the higher the permeability is the lower the frequency must be. Also in general the losses in the coil are higher as permeability increases.

Oh thank you xee2,
That is exactly what I needed for the conceptual to get me started.
thank you
thank you

Also, I am glad to know you use more than single layer.

thank you,

jeanna

[nievesoliveras]

@all

There has been one successful replication and one not successful replication of the joule thief self charger.

This is the successful one.
http://www.overunity.com/index.php?topic=6362.msg183456#msg183456

Edit:
The photo is not from @wilbyinebriated replication.