Joule theif : try out !

[omdano]

Hello i just bought a couple of peltiers and i want to light a led with 20/30mV with a joule theif

i am new to this forum so.. can anybody be a dear and give me a schematic and suggest me some transistors i can find in market ?
(this turned into my new hobby :p )

Thanks guys

[TinselKoala]

Oh yes. You should look at the various JT threads here. It's kind of surprising that none are active at the moment. There are many many circuit variations.

Just about any NPN transistor will work, but good ones for low-power are
BC337
2n2222a
mpsa18
2sk170

You may find this video amusing:

http://www.youtube.com/watch?v=tuFWC-yyIyU

[xee2]

Hello i just bought a couple of peltiers and i want to light a led with 20/30mV with a joule theif

i am new to this forum so.. can anybody be a dear and give me a schematic and suggest me some transistors i can find in market ?
(this turned into my new hobby :p )

Thanks guys

A Joule thief generally requires at least 0.7 volts to operate. This can be reduced to about 0.2 volts using germanium transistors as in http://www.youtube.com/watch?v=XQ7dua2mBzo. However, I do not think 30 mv will work.

[TinselKoala]

Ah, you are right. For some reason I read the OP as "20 or 30 milliAmps" instead of mV.

The lowest I personally have seen one work is about 300 mV on the supply.

[omdano]

What about this thread ?

http://www.overunity.com/13175/25mv-joule-thief-powered-by-peltier-merely-using-our-body-heat-free-energy-247/msg348682/#msg348682