Joule Thief

[gadgetmall]

@MrMag
thats a Neon you got there . how about a regular Jould Thief  Just that runs an led not a Hv  jt like fugi . Just curious now that you have a Great Setup to Measure !!!Look s   Great !

[Pirate88179]

@ MrMag:

Nice work!  That is good information to have...and yes, I wish we all had scopes. Interesting that you got 12 KHz on your JT.  Am I correct in thinking that unless we all used the same transistors, and resistor and the same ga. wire and same number of windings and the exact same toroids, that this will vary out here among us?  Or, does the transistor and resistor themselves determine the freq.?

@ Gadgetmall:

I may be wrong but I believe that all JT circuits are high frequency.  That is why I did my sound tests on both the Fuji and the toroid versions.  I just think the Fuji is higher in both frequency and output due to the nature of the size of its coils and windings in the transformer.  I am not sure about this, of course, but it makes sense to me that this would be true.

PS  I just looked up the specs on the 2N3904 transistor and it says it will operate up to 100 MHz, for what this is worth.

Bill

[xee2]

@ electricme

Now that is a BIG toroid. I suspect it came out of a very expensive amp that used ferrite instead of laminated steel for the output transformer in order to get better high frequency response and is big in order to have low distortion. That should make an excellent Joule thief. It probably is already wound so that you can use three of the connections to make the Joule thief and the other two will act as an extra winding that can be used for AC output.

[xee2]

@ MrMag

Great photo. Thanks for posting it. You are correct, the only way to get accurate measurements of AC waveforms is to use a scope. I hope more people with scopes will post photos.

EDIT: Where is scope probe attached to circuit? It looks like you are measuring the voltage across the neon bulb which limits voltage to about 90 volts plus and minus (180 total for AC). The little spike is the voltage before the neon turns on, but is so quick the scope is not getting a chance to display it. If you remove the neon I think you will get a better picture of the Joule thief output voltage (it will be much higher).

[innovation_station]

 

thank you mr mag!!

i will hook up my scope ...

i will need some guidence if you dont mind

i will find my probe with adjustable x.... settings

but im still winding got 6 done

6 more to go but each and everyone is perfect so far .... 

ist!