Joule Thief

[dog812]

Thanks for the info everyone..
I see there is a lot of different readings from different items used..
I thought there might be a rule of thumb or something about more or less turns.. but i see its trial and error..

I took apart my secondary and made it 22 turns ..  it still doesnt light the second LED in paralell very well.. so maybe ill try a new torrid and use less primary turns..
Thanks again.

[altrez]

@all

Just an update.. I have fallowed everyone's excellent advice and tried 10 different configurations tonight. Still no luck with the pickup coil. Once I can get it to work I will post a step by step of what it took. So far I have used 4 different toroids 3 different types of wire. Tested everything at least 30 times. And have had one of my friends give it a try as well and he could not get it to work either. 

All of my JT circuits always work perfectly and the toroid from the last picture I posted is lighting a grand total of 35 LEDS!@!@!@! It will not accept a pickup coil however. No matter how I space the bifilar turns or where I wrap the pickup coil.

My best guess is that I need to order a toroid that works with a pickup coil and that others have had success in adding a pickup coil.

Thank's!

[dog812]

P.S. Someone mentioned a "potentiometer"
Is ther any certain specs on this thing i shold be looking for.. or
this is my local electronic store i shop at.. if you can tell which item to go get from here. that would be great..
http://www.rpelectronics.com/

[innovation_station]

 

notice the alum i posted 2 machined aum rings ...  alum wire ....

will not be used as showen

lol

dont go thinking it is a jt on an alum ring ....  lol

i WILL CUT THE RING ...   lol  i will then insert a relay COIL ... 

LOL

ist! 

same goes with the wire ...  why?!?!?!?!

[TheNOP]

The NOP just said hi permeability is good. I am not sure at all if that is true.

My high permeability toroid which cost me a lot more than the others performed miserably. Because of his post, I may recheck it, but for now, I think that came out of a text but not experience with a working jt.

high permeability, yes, but permeability is in relation to the frequency.
you must choose the core material with a frequencies range in mind.

high permeability + highest frequency capable toroid are not good for a jt.
but most toroid can be somewhat fixed to work in a jt circuit by spreading the coils all around the core and/or adding more turns on all coils.


what i wrote on cores was from both, text books, and from experience.
not only with the jt but with other transformers too.

i do recommend that peoples look those infos up by themself.
and most important, please, correct me when i am wrong.