Joule Thief

[the_big_m_in_ok]

xee2 said to kooler:

@ kooler ...
What kind of transformer are you using? ...

@ all
Radio Shack used to sell a little audio transformer whose secondary had an impedance of several thousand ohms.  (It weighed about 1/2 ounce.)

Would two of such transformers in step up series simulate one of those Fuji-style flash unit transformers?

--Lee

[kooler]

the little transformer i have is one inch tall and one inch wide...
it has 4 pins on one side and 2 pins on the the other
the 4 pin side reads 0.9 ohms  (input)
the 2 pin side reads 70.7 ohms (output)

the code on the transformer reads
on top (0209 lae)
bottom (47j00-0080e lae)
yellow band
ferrite e-core

i think it is a tranny out of a toshiba satellite box

[Pirate88179]

kooler:

Try running the name and then the specs on a google search.  You might just be able to come up with some specs on it.  I have done it.  Sometimes it works, others no.

Bill

[xee2]

@ kooler

oh i meant to you all that if i run a small 3v battery in ..
i can discharge the 3uf cap fast enough ..
i can take to leads and shoot constant sparks like i welding... its pretty kool
just don't do it to long it will weld the leads together

Bend two  wires so they are closer together at the bottom than the top and adjust the gap at the bottom so it is small enough for a spark to jump across. The spark will rise so that heat is not all in one place on the wires. Attached video is of Joule thief powered by two 1.5 volt AA batteries. Output is directly from pickup coil winding, no rectifier or capacitor is needed.

EDIT: Sparks put out high levels of UV radiation and can damage eyes with long exposure. Use UV blocking sunglasses when looking at sparks.

[stprue]

@all

any luck replicating Koolers last circuit?  No luck here!!!  I was able to light a bulb with my TPU for a few sec's but nothing good to post!