Joule Thief

[xee2]

@ dog812 

Interesting test. I would think that it would work OK but it doesn't. That is the value of experimentation. Some people say that coils work better when they are tight against the ferrite, but I have made many coils with turns not tight (like your white wires) and they worked. I never did any tests to see if they worked better when tight. However, I do think that the way you have made it may be reducing the coupling between the collector coil and the base coil, since both of them are probably more tightly coupled to the secondary than to each other the way you have made it. I do not know why that would make using a resistor a problem though. I would think that it would make it necessayr to use a larger resistor. Which is another example of why testing is the only way to tell if it will work.

[Mk1]

@Dog812

I tried and got better result when all coils are starting and ending at the same spot on the toroid, you really should try.

Mark

[resonanceman]

Anyone tried putting the secondary under..?
It works pretty good.. but i cant get it to work with a resistor..in this pic i am using a pot.. but i have it maxed out in order for it to work.
6-6 over the 30 turn secondary.
http://www.postimage.org/image.php?v=PqnlDQr

Dog

I have tried   putting the  secondary  under the  JT windings ... I have not had much luck with it so far .
IN theory it should  work  great there ....... it  should  be  in position  to catch more of the  flux .



gary

[resonanceman]

Duplicate  post  deleted 

[jeanna]

Anyone tried putting the secondary under..?
It works pretty good.. but i cant get it to work with a resistor..in this pic i am using a pot.. but i have it maxed out in order for it to work.
6-6 over the 30 turn secondary.
http://www.postimage.org/image.php?v=PqnlDQr

Hi Dog812,

By maxed out do you mean zero ohms.

This is very interesting, esp. in light of how N Tesla insists that he gets better results with the secondary inside.

I wonder if there is any sparking happening in the coil reducing its strength. I read how NT had to bury his thin wire in oil to prevent gratuitous sparking that reduce the effect he was looking for.

OIL no good on Hula Hoops. yuck.

This is reminding me of a toroid or 2 that I consider unreliable because sometimes the results are good and sometimes terrible and the only thing that changed was a breeze in the room. I wonder. The sparks can be too small to see. Especially at high frequencies.

Maybe that is another hula hoop product.
Sparks as the hoop turns. That would look really cool.

In the book about/by Tesla that I am reading he says this is the reason he prefers secondary wire to be covered by gutta percha. This is latex rubber and withstands a lot before breaking down and permitting a spark.
(I wonder if Kynar is aluminum covered with gutta percha? same rubbery feeling hmm)

@xee2, Is the sparking the same thing as the capacitive coupling you EE educated guys talk about?

@MK1,
I have also tried winding all wires to the same place and it does seem to help. I am not ready to say it is necessary, but I am ready to say always try it before giving up on an idea, because it may make the difference.

==
quote from the book:
p.217
" In trials of this kind* the experimenter arrives at the
startling conclusion that, to pass ordinary luminous discharges
through gases, no particular degree of exhaustion is needed, but
that the gas may be at ordinary or even greater pressure. To
accomplish this, a very high frequency is essential ; a high po-
tential is likewise required, but this is merely an incidental neces-
sity."
*He is making high frequency sparks pass through a wire. The wire or the entire space between 2 wires or the wires themselves etc. become illuminated.

from the link MK1 provided the other day to scribd.
http://www.scribd.com/doc/13040608/The-Researches-of-Nikola-Tesla-1894

very interesting lecture.
=====

good pic, btw.
thank you,

jeanna