Joule Thief

[jeanna]

Ah xee2, there is a good challenge!
I am not interested in using a manufactured chip product so I would want to wind it myself.

@Mk1 (particularly),

As you may remember I just purchased a LC meter.
I have spent some time cataloging my many hand wound toroids and I would like to describe briefly ?? if I can

The inductance for half the bifilar primary is often 1/4  rather than 1/2 of the combined bifilar.
So, the inherent multiple directions is making a greater difference than the number of turns by itself.
There must be other factors at work too, because I cannot make a rule out of just the turns and number of directions, but it is consistently this.
Now, remember this is not a selection of randomly made toroids. They have all been shown to be good performers.
I have some that are bad performers and I will look at them separately.

Now here is a sweet bit for the MK1 and MK2 pickups.

They provide the same bonus inductance that I see with the primary bifilar windings.

I might be making a table for myself so I can study the numbers and I know unless I do that it is too difficult for me to explain and for people to understand.

But I must say that the inductance of the MK1 is amazing but the MK2 when all lines are connected is even more.

For instance the separate legs of the primary are each about  .080mH and add up to NOT .160 but .320mH

Then each half of the MK2 which by itself is a single wire just like a MK1 measures
8mH and together they are
NOT 16mH but
34mH

I still need time to digest this, but I thought some of you guys would like a chance to hear about it too.

jeanna

I am thinking the value in all this information might be to guide us in the choice of a capacitor to use to aid the oscillations that WANT to express themselves. If we do not change the other parts of the circuit by a factor of 4 (not 2) we may be choking the inductor and not able to get full benefit for this reason.

[xee2]

@ jeanna

Inductance of coil increases as square of turns. Thus doubling turns produces four time inductance.

Equations here: http://www.phys.uri.edu/~gerhard/PHY204/tsl267.pdf

chart here: http://www.gqrp.com/toroid_inductance_chart.pdf

Your measurements seem to confirm theory.

[xee2]

@ jeanna

I am not interested in using a manufactured chip product so I would want to wind it myself.

Are you going to take the core out of a flyback and wind your own coils on it? It would be interesting to see how much better the laminated iron core "toroid" works than the ferrite toroid.

[tagor]

double post

[tagor]

Humm ... You can read french ... but thanks for the info anyway.

Merci . Don't you consider a magazine article enough ?

you can ask me every thing ( inn french ) in this thread

http://www.overunity.com/index.php?topic=4744.msg98997#msg98997

a lot of people tried to replicate the D'HOKER device
but no OU !!

this magazine is a very bad scentific magazine , no proof