Joule Thief

[jeanna]

Thank you xee2,

I am still wanting to verify that I am using the right scale on the scope. I don't trust it or me.

So, I took the 2 secondary wires A and B I put a diode on the end of each one facing opposite directions and used these to fill the cap.
That was that.

I was surprised with how very low it was, so I hooked up the full bridge rectifier again.


I stuck A and B into their own slots in a breadboard and in the same columns I put a wire each of which was connected to the 2 ~ spots in the bridge. (600volt bridge)

So now, instead of just reading the outside posts of the rectifier I must wire a cap to them?
Is 100pF enough?

Thanks,

jeanna

[jadaro2600]

I'm getting unusual results too, but I have no oscilloscope, I can only go on intuition.  So I've been asking a lot of questions lately.

[resonanceman]

Does anybody have any ideas?

BTW the reason for dropping back a bit is because the other day I had a pretty steady series of waves at 120 volts and this did not light my string of christmas leds.

thanks,

jeanna

Jeanna

Voltage  alone is not enough  .......  you need  enough  current .

It  is my experience that when I connect  a JT or camera circuit  to a load that is to large  I get nothing .......it is like the load just  sucks  up the  energy from the JT
I remember you saying that your   transistor never gets hot
I use a pot on  mine ....... I check to see what it does as it goes through  the whole  range of the pot .....  I  also  check the whole range  with  several different caps .........MOST of the time the highest voltages  are with  very low  resistance and no cap ......

Remember   a while  back there was talk   about  inducing  power in  more than one secondary ?
Someone said that you can't   take more  power out of any secondary than you put into the primary .... ......so I suggest  you  lower   the resistance on the base  of  your transistor and let it heat  up  just a little ..........or  add another secondary or 2  and  use them in parrallel

gary

[xee2]

@

So now, instead of just reading the outside posts of the rectifier I must wire a cap to them?
Is 100pF enough?

Yes.

To check your scope, you should be able to measure the voltage of a battery with the scope and then compare that with the reading on the voltmeter.

[jeanna]

Thanks xee2,
I am learning things that are obvious to anyone who has used a scope.

What I had to learn by trial because it was not in the manual, is that the probe can be x1 or x10 and the meter can also be x1 and x10, but that is probably to get a close resolution. I need to know what is the real reading. I have learned how to do that by what happened with the cap and bridge today. (I hope.  )

Perhaps you can save me a week or longer...?
I can switch the speed from 12Hz up to 240kHz - I can't remember the top.

What does this mean? Is this the length of time between the time markers? perhaps the meter is sampling at this rate?

I sometimes see what looks like a real close up but continue to move the meter in the direction that showed me the close up, and it again looks like a long shot not a closer up shot. This is the reason I cannot figure out what it means.

If I were looking at anything close to normal, it would be easy to guess right.

Thank you,

jeanna