Joule Thief

[xee2]

@ jeanna

I looked for some data on 2" cores but did not find much. I did find this, which I am sure is not the best design but shows that a 2" core will light fluorescent tube.

[gadgetmall]

Thanks gadget,

This is not the same toroid.
Mine is dark charcoal color. Yours has the grey paint.
So, it might be very different.

But if it is not shorting, then maybe the primary is not turning the transistor on (or off)
So, it could be the primary,
or
the transistor,


Is it possible that the primary wires got mixed up and you no longer have the center tapped?
I am not coming up with much here, I know, but 420 turns  will get you around 450 volts and more.

Is that a new transistor?

Is the wire scraped off enough? (that is usually my problem)

Maybe I will think of something else.

jeanna

O i thought someone said it way gray . O well . I blew My last tip3055 on the 800 volt little one so I need to pick up a few tomorrow . I'll try again then . thanks 4 the help .

Need to put little one to sleep for school . Gnight

Gadget

[jeanna]

OK gadget, let us know.
btw...
Do you have meters?
A  LC meter, perhaps or a scope?
I have been finding really good info from this.

@xee2,
Yes, that is the one I was thinking about.
I am glad and you did actually light one as I recall. A 4 inch.

I was able to light a 4 inch with a 1 inch tor-61 from allelectronics.
Funny it has half the needed voltage now. I cannot figure what happened, but I plan to wind another.
This is 45 cents, and if it can do the job, then  'jeanna's light' , which is the result of all of us working together will be a good success.

@All,

I have been making some turns:inductance studies with my toroids.

This latest batch was the klinkers batch, and I am really seeing why I do not like these toroids.

The first is the exception, so I will get that out of the way.

The goldmine 5/$1

2T=   36uH
7T=  411uH

So, These are the inductances that have been working to make good jt's with the other toroids, so I looked at the 5/$1 on the scope, because it has 2 secondaries already wound on it.

So this was a jt with 2T,6T and a 6T pickup
42v
16.6khz
seems good enough.

also
2T,6T, a bunch of green mag wire maybe 25 T
212v
7.69khz
This should easily light a neon but it does not.
This is the kind of thing that makes me not like this. I think for 212 v the frequency needs to be higher, but the wave shape is a long straight line then a triangle then a long straight line.
It might be the lack of sharpness.
OR something else...

'Bad Blue'
This must be a choke.
No inductance until 4T then a tiny bit.
and 7T only gives 8uH  .00
I have never mentioned this but no turns meaning the base measurement of the meter is 3uH so you must subtract that to find the real number.
I never bother because I tend to sometimes forget, but in this case I must mention this.

the' choke'

6T        3uH the base measurement therefore 0
19T    20uH
So, to get this to do anything I need to wind 20 turns for the base coil then many more like 60 or 80 for the collector coil. I wasted $36, and that is all there is to it.
------

The numbers I have been using these last 3 days are
~30uH for the base coil, and
~250-275uH for the collector coil
This will give you an idea of how far off these klinkers are  from good jt core material.

I hope this helps to keep people from wasting their money.

jeanna

[Magluvin]

Hello all

Been checking out what you have going on here and it is very good. Has anyone tried an air core coil for these setups? I read just recently that inductive cores slow down the build and collapse of the mag field. Just wondering if it makes a difference here or not. =]

Magluvin

[WilbyInebriated]

Hello all

Been checking out what you have going on here and it is very good. Has anyone tried an air core coil for these setups? I read just recently that inductive cores slow down the build and collapse of the mag field. Just wondering if it makes a difference here or not. =]

Magluvin

i have. here is the post. http://www.overunity.com/index.php?topic=6123.msg143373#msg143373
i also have a very tiny aircoil jt where the coils are wound directly on the transistor body.