Joule Thief

[jeanna]

@Mark,
There are lots of numbers with the more turns on the collector and when I changed to the more turns on the base, I just swept the pot dial till it looked better , then made another turn and did that again.

The overview answer to your question is well, it is close but not right on.
I was at 3T,12T,240T and

When I first turned it around to 12T,3T,240T
I swept the pot and stopped in 3 places.
2k930r   131.7v  14.2KHz
1k100r   170v     14.2KHz  same resistance but not same voltage output.
320r       189v     13.3KHz

With
13T,3T, 240T 
500r       183.7V   13.3KHz

added another turn
14T,3T,240T
500r        168v      13,3KHz  the best score but less volts than the last one.

Added one more to the base but went back to better base turns of 13
13T,4T,240T
90r           186v      9.52KHz

Now, how to describe this??
If I pull way back on the scope so the wave is just a little bit of bumps, the scope will tell me a much higher value for the total voltage. (theNOP explained this to me a while ago. )
There are 3 configs that give me 192v when seen from way back.
12T,3T,240T
320r       189v     13.3KHz
13T,3T, 240T 
500r       183.7V   13.3KHz
13T,4T,240T
90r           186v      9.52KHz

And another piece of information on thei.
I never found a sweet spot.
I did find a poison spot.
Same thing only different.

jeanna

[Mk1]

@jeanna

Cool , info the voltage reading sre the same on the scope and on the meter ?

Also i wonder about 4t 4t or 5 t 5t or 6t 6t on the jt side.

That way the have the same mass .


Mark


Edit  is your jt is repulsing mode or attracting .

[jeanna]

@jeanna

Cool , info the voltage reading sre the same on the scope and on the meter ?

Also i wonder about 4t 4t or 5 t 5t or 6t 6t on the jt side.

That way the have the same mass .


Mark

Meter? what meter?
---
Don't you mean
12T,12T
13T,13T
14T,14T

3T3T etc won't even turn on. They need 12T on the base.
I had to go to 90r to get that good reading the rest was way down, so I think adding one more will be worse. I probably will do that tomorrow, just to finish this level of the tests.

As I added one more to 4T on that last reading I had to squeeze the last bit of wire to do it.

If you look back to the pic I posted this morning, you can see an old few-turns primary on the bottom. I started there and the thing would not oscillate without a cap.


I do see the reason to make 12T,12T, but just to see. I think it will kill it.

jeanna

[Mk1]

@ jeanna

The freq on the scope and the voltage on the bridge with a multimeter set to volts.

It dosen' t turn on with 12t 12t , humm , you may be in repulsion mode .

That would also explain the problem with the connection in series , since both ends of the coil have the same polarity.

I have better result with 2n2222 , but there not all the  same some are just bad.

the resistor value may not be the usual it may be higher then expected.
Mark 

[jeanna]

@ jeanna

The freq on the scope and the voltage on the bridge with a multimeter set to volts.

Sorry, You can do that. You won't get me to do that again, for sure!

It doesn' t turn on with 12t 12t , humm , you may be in repulsion mode .

NO I said it doesn't turn on with low numbers the way most toroids have in my past. I used 2 and3 with 5 and it did not turn on.

I have not tried 12T,12T, I will need to see if that is a good one or not.

I have better result with 2n2222

They work fine too, but they always take more amps from the battery to produce the same amount of volts from the secondary given a particular toroid and circuit.

the resistor value may not be the usual it may be higher then expected.

I have had a rash of these lately, and I am glad to know this can happen this way.

jeanna