Joule Thief

[xee2]

@ jeanna

I did mean divide. That is about the only thing that is clear in my manual. ... I think...

The 10x probe means that the voltage at the tip of the probe is 10 times larger than what goes to your scope. Therefore you need to multiply the scope reading by 10 to get the voltage at the probe tip. Some scopes will sense what probe is set to and automatically adjust the value displayed so that no multiplication or division is needed. Sometimes probes are marked divide by 10 instead of 10X, but both probes do the same thing - it is very confussing but that is the way it is. That is why I suggested checking the scope scales using a battery.

[jeanna]

@All,
I noticed something I didn't test last night, so before I change the toroids I am using I want to report this.
This orphaned wire may be causing it I don't know.

It is repeatable.

Amps draw in the BJTL place on the second tier can have parallel lights and the addition of those lights REDUCES the draw. It does this by 1 milliAmp per led. Also, bye the way, the light here in this BJTL spot is great - very bright and does not diminish with the addition of more in || with it.

Whereas the ones on the second tier secondary draw more microAmps with each additional one added.
Also, all the ones on the second tier secondary are quite dim.
This would be expected in a normal ckt, but is only true on some jtc's . (I believe those times are when there is a wide difference between the number of primary winds and secondary. not sure.)

I think it is especially odd that there is big reduction -mA- with || leds in the BJTL spot and small increase -uA- in the secondary.

Has anybody else noticed this in their regular jtc's?
There are several people who have found better results using parallel lights in the BJTL spot.
Have any of you also managed to wrap a secondary and get it to light?
If you have, what is the behavior of the amps draw with the addition of the lights in the different places?
Either or both. Any info on this is valuable.

This may shed light on some of our outstanding questions.

thank you,

jeanna

[jeanna]

@ jeanna

The 10x probe means that the voltage at the tip of the probe is 10 times larger than what goes to your scope. Therefore you need to multiply the scope reading by 10 to get the voltage at the probe tip. Some scopes will sense what probe is set to and automatically adjust the value displayed so that no multiplication or division is needed. Sometimes probes are marked divide by 10 instead of 10X, but both probes do the same thing - it is very confussing but that is the way it is. That is why I suggested checking the scope scales using a battery.

Hi xee2,

I must correct this first. It is x1 and x10. I probably wrote it backwards.

This one does not sense it. I must do it myself.
I just don't think I am ever getting over a thousand volts! Or even 735 volts. I am sure that is 73.5 volts. And, in fact this is what drove me to get out that full wave bridge and fill a cap.
And, darn, the cap didn't agree with the scope or the dmm. I believe the cap. It could not be getting more than what is going in... and, yes, I always short it first.

I wish I could figure out how to get this thing to show me the dc of a battery. It is available, but I can't figure what series of buttons to push to get that screen up. There is a real estate problem on the screen. It is 2 inches tall by 3 inches wide and can only show so much, as you can imagine.
I am blaming the terse manual for my difficulty.

I have not been ignoring your suggestion. I just haven't been able to get the thing to show the dc.

thank you,

jeanna

[xee2]

@ jeanna

I agree with your reasoning and you have more information than any of us, so if anyone is correct I would assume it is you. But what you are reporting seems strange. Most scopes have a knob that can be set to AC or DC input. But since your scope is digital this is probably set in a menu somewhere. Once you find where to set it. Then you can just set the sweep to its slowest rate and then intermittently touch the probes to the battery terminals and the trace should bounce up and down as you do this. I don't know what else I can say that might be helpful. Good luck.

[jeanna]

OK everyone,

Check THIS out:

I put in another jtc to test and while fiddling the second tier secondary came out of its place in the neg side of the LEDs. As I was trying to return it to its slot my hand slipped!!  and the wire hit the negative side of the battery rail. all the lights got bright. the amps draw lowered and now, we are in business.

I made a preliminary drawing. As you can see there are 8 lights now, 4 in the bjtl spot and 4 in the secondary spot all in the second tier.  OMG. this is too cool. I put this secondary in the battery rails yesterday but not before the orphaned jt wire came out. IT as you can see because it is attached to the yellow clip is in the neg of the leds that are also connectedon their pos side to the one legged secondary.

ooo too cool.

jeanna

EDIT
I am sorry. I just realized the leds were the other way around. I hope I made all the changes to the above text correctly and here is the new pic with drawing.