Joule Thief

[xee2]

@ kamax

This worked for me. Toroid is $3.50 from:

http://www.allelectronics.com/make-a-store/item/TOR-60/3.38-DIAMETER-FERRITE-TOROID/1.html

Cut length of wire needed then wrap it around a small diameter tube and thread tube through center of toroid. It only takes about 1/2 hour to make it that way.

[protonmom]

Hi everyone.  I am still trying to read the entire thread, but I have not even gotten to page 100 yet...so I have no idea what is going on currently.  However, I have a question, so please forgive me for jumping in here.  And if this has already been answered somewhere, just tell me which post/page to look at, okay?  I have a bunch of I-zone cameras and decided to open one up to see what lies within.  Does anyone know if this circuit board can be used in any way for a joule thief?  I will try to upload the picture.  If it is too big, I will have to try again later.  Any help would be appreciated.  There are so many geniuses here, that someone should be able to tell if this can be used.  Thanks in advance.

[jeanna]

Hi protonmom,

My answer is I dunno.
Wilby had a great system for doing almost any camera circuit, I think you can find his system in the form of a drawing on the thread Bill made with just the circuits.

I was able to light a fluoro from the AA kind when I put the ends of the fluoro tube between the wires where the cap was.
So, remove the cap but leave some wire so you can connect it.

Short the cap with a screwdriver before you go near it and once for good luck after . It isn't going to really hurt you but I do have a charred spot in my grandmother's tablecloth! (oops!).
( It is enough voltage to hurt you but you must touch each end with a different hand, and that is pretty hard to do when the leads are 3/8 inch apart.)

Anyway try that first.
There are better camera experts than I am.
But, that just might work.

The next thing to do is to short out a diode. If there is only one, you can do that, but if there are 2, I need to back out, cuz I am not sure.

jeanna

[kamax]

Thanks for your help Xee2. I have changed my primary 2t/10t but i can't light the tube better. And when i put a bridge+cap i read only ~80Volts.

After that i have changed again my primary to a conventional bifilar and an increase of voltage for each turn:
-2 turn ~60V
-3 turn ~90V
-4 turn ~120v

So, +30V for each turn but with more that 4 or 5 turn, the increase is not so important. I have now 13 turn and ~170V. But the tube don't light if i connect it like your last pic. The "wireless effect" was not so important as previous and touching some wires hurt my fingers enough that i remove them very quick.

Then i have play with the resistor who change the max output and the noise of the toroide. I have increase the value and the voltage go down but higher frequency noise.

With more high noise/frequency from the toroide, i was able to have a very good wireless effect even the voltage is not on the max. And i can touch every wires without pain this time. I can light a side of the 18W tube but not all.

Does someone know it the wireless effect i have is magnetic or more a sort of radiant energy ?

[xee2]

@ kamax

Does someone know it the wireless effect i have is magnetic or more a sort of radiant energy ?

The wireless effect is capacitive coupling and increasing frequency will also increase the amount of energy coupled through the capacitive coupling.

You seem to have a very low permeability toroid. This aids wireless coupling but produces less inductance per turn. You may need to use a different toroid (with higher permeability) to be able to light the tubes.