Joule Thief

[freepow]

  Hello Jim,  A few months ago when I measured my double toroid JT,
I measured with 1xAA at 1.267v   =   821v
                       1xAA at 1.390v   =   925v
                       2xAA at 2.727v   = 1248v  I measured these several times with same result.

And presently when I measure with 1xAA, I now only get around 359-450v about 1/2 of what I got few months back !

So I made another exact double toroid and it still measures only 1/2
So I am thinking that after what you said about damaging the DMM with HV, that maby I have damaged it slightly where it is not measuring it properly anymore

What do you think???

[jeanna]

freepow,
Maybe one time it was on AC HV and the other time it was on DC HV ??

jeanna

[MrMag]

Put your meter on AC volts and plug it in the wall and see what it reads.

[freepow]

  @ all,  A question for anyone who may know the answer...

              When I connect my DMM to my JT, I get a quick HV spike, then it go's down and settles,
              which is the most accurate one out of number 1 or 2
               
              1 - The high spike ? ...( I can quickly press the hold button to read this reading )
              2 - Or the lower result where the DMM reading settles ?

              I know I have been told that the DMM reading the volts from a JT is probably not accurate
              but still want to know out of number 1 or 2.  Thanks.

              One more question, if anyone knows... Would a low frequency radio scanner or frequency
              counter with a broad range of say 100Hz to 1Ghz  be able to read the output
              frequency of a JouleThief            

[MrMag]

@ all,  A question for anyone who may know the answer...

              When I connect my DMM to my JT, I get a quick HV spike, then it go's down and settles,
              which is the most accurate one out of number 1 or 2
               
              1 - The high spike ? ...( I can quickly press the hold button to read this reading )
              2 - Or the lower result where the DMM reading settles ?

              I know I have been told that the DMM reading the volts from a JT is probably not accurate
              but still want to know out of number 1 or 2.  Thanks.

              One more question, if anyone knows... Would a low frequency radio scanner or frequency
              counter with a broad range of say 100Hz to 1Ghz  be able to read the output
              frequency of a JouleThief            

I am really not sure which reading would be more accurate. Have you tried winding maybe 10 turns on the coil and read that voltage. You could then multiply that by the number of turns on your secondary. It may give a closer approximation of the voltage.

I'm not sure if you have enough RF output to get a reading but it would be worth a try. You really need to get a scope.