Joule Thief

[jeanna]

@ jeanna

That is strange. I would expect that there would be at least 10 VAC there.

Thank you xee2,

I don't get where your numbers come from. Of course if you built one, it would be from experience.

In my efforts to learn about circuits I set myself the problem of getting the best brightness and the longest life from the battery of my led candles. I was all over the net studying things with dt's and equations I don't remember how to work. I  know there is a lot to the equation that describes the amplification effect gained when the base allows a certain amount of voltage through to the emitter(?) etc... but the numbers were all in the 20-30 milliamps range and all aimed at keeping the voltage to the base resistor at or around 0.7V so none was wasted, etc.

Nothing was in the neighborhood of 10 volts or egads 20volts.

So, if if it possible to explain it not too obscurely, I, for one would appreciate hearing and learning about how you expect it to be so high.

Thanks for checking. I am not sure what is going on, so I guess the best thing to do is just keep experimenting.

Always

Thank you,

jeanna

[Mk1]

@jeanna and timmy

I got those video for you they will be a great help . The first one is on transistor , really nice one.
The second is on diode for Timmy.

http://www.youtube.com/watch?v=eZDxYHEuy_g&feature=channel_page

http://www.youtube.com/watch?v=PdZKxtc8cq8&feature=channel_page
http://www.youtube.com/watch?v=_sZJgQfO5wg&feature=channel
http://www.youtube.com/watch?v=UvHCQswnjEg&feature=channel_page

[xee2]

@ Jeanna

I did a bit of playing around to see what I could do. I was using a larger toroid, so that may have made some difference. But I was not using an LED between the collector and emitter of the transistor like you are. I wonder if you would get more voltage on the secondary leads if you removed that LED. All of my LEDs were between the secondary leads. It is best to have half of LEDs with + in one direction and half with + in other direction so that half are lit during each half cycle of the AC.

If you want the best brightness and durations you need to find LEDs that are good for that. I have some LEDs that light bright (well maybe not very bright) on 0.0078 ma and 2.38 volts. I bought them at surplus store and tried to find out who made them, but no one knew. They were marked green super bright 15,000+ MCD at 50 ma and 3.6 volts. One of these LEDs should theoretically light for 8 years using two AA batteries. Or 100 LEDs for one month. I will try to dig one out and post a photo tommorrow.

[Mk1]

@xee2

I never use the led on my joule thief experiment, and got better results than anybody that might explain it.

Very very good.

[electricme]

@all
I just found a nice bit of info on winding ferrite coils, this is a little different though, this chapp uses the vertical transformer bobbins.

Let me know what you think about making a 5 bifiller secondary coil?

click here to go to it  http://www.users.on.net/~endsodds/tx.htm


jim