Joule Thief

[xee2]

@ jeanna

For JT you want the highest permeability you can get. That gives the most inductance per turn and that gives the highest voltage pulse per milliamp. The high permeability cores become more lossy as the frequency increases. Thus at higher frequencies (around 10 MHz) they have too much loss and lower permeability cores are needed. In addition to the permeability, the shape of the core should be considered. If you would with the site you were at you will see what parameters increase inductance (which is what you want to do to get the highest output voltage).

I hope that helps.

[WilbyInebriated]

I am doing as bill asked me to.
I tried to dissuade him, but to no avail.

Bill has left this forum.


jeanna

wtf??? wow. well, as a show of solidarity unless bill returns i won't be posting at this forum any longer either.

[jeanna]

I hope that helps.

Thanks xee2,

I just wrote to one of the distributors.
I hope we can find something standard.

@Wilby,
Things have changed etc.
Please read on beyond that first post.

jeanna

[xee2]

I bought a 13 watt CFL today and tried it out. I had no problem getting it to light up completely when battery was connected but it does not seem as bright as Lidmotor was getting. So maybe the extra turns do help.

EDIT: I added another photo. It looks brighter when it is standing up.

[jeanna]

xee2,
All I told him was to get above 450 volts.
Then I told him what I used.
It was because lidmotor said he had over 1000 volts that I tried the new transistor and reduced the primary turns on last summer's core.

13 watt is not as bright as 10 watt. I do think that is interesting.
I see it with leds too.
If I have fewer leds to fuller brightness it seems brighter than many more with less brightness.
It is so subjective I haven't mentioned it.

There are a lot of elements working together.
I think the transistor makes a big difference too.

Why not put on 120 turns instead of 80.

I just tried the high permeability toroid and the new one.
I just put on the turns needed to get the same inductance I have in the big one and the joule thief takes off.

This is so interesting.

jeanna