Joule Thief

[Pirate88179]

Jeanna:

As I said before fixed the end of your video, nice job.  I really think you should get an award for that.  I am serious.

Did you say what voltage you were able to obtain from that small painted toroid?  I have some new ideas I have been thinking about that I want to try but, I have to pay some bills first.

Again, excellent job there.

Bill

[jeanna]

Hi Bill,

I got 55-65 spiky volts with 10 turns. It was just a preliminary try.
Later I wound 3 or 4 more turns to use the remaining wire and I checked the voltage before risking the leds, and the volts were 65v at 63 Khz, but now,  they were steady and did not dip into the 50's. I know the pic says 59v but that was before I added the last few turns.
I got almost 4 volts from 1 1/2 turns, so I lit that one led and it was bright too.

I just hope people will be able to make their own. It was not a teaching demo, of course, but just information of what is possible.

High hopes for the world,

jeanna

[crowclaw]

@ crowclaw

Your scope shots are excellent. Would you be willing to post a dual trace shot with the CE on one channel and the voltage across the base resistor on the other channel? I do not have a scope so I can not do this, but I think it would be interesting.

Hi xee2,
Hope tyhis scope shot is ok. Channel A = CE and channel B = BE junctions. Regards

[crowclaw]

@ Jeanna,

Excellent video and well done to you. I will try out what you say but I think the better plan is to remove the windings and do as you have done. The CFL toroid has three colours, green = 9 turns, black = 2 and yellow = 2. Didn't use the yellow. The green I used for the collector and the black for feedback to the base. Again it was just to show what could be achieved.  merv

[xee2]

@crowclaw

[A author=crowclaw link=topic=6123.msg226107#msg226107 date=1265049750]
Hi xee2,
Hope tyhis scope A is ok. Channel A = CE and channel B = BE junctions. Regards
[/quote]

Unfortunately it is very hard to see the trace for the voltage across the resistor. Is it where I have marked? I was hoping the resistor voltage would show that current reversed in resistor before the C-E spike. In any case, your help is appreciated, thanks. If I understand your scope shot it would seem that the voltage across the resistor never goes negative and thus the current does not reverse in the base resistor.