25mV Joule Thief powered by peltier merely using our body heat -Free energy 24/7

[magpwr]

Oh sorry i forgot to say that my peltier produces about 100mV and i am going to use 2 to produce 0.2
i want a transistor for a 0.2 JT XD , can you help me with that one

thanks
God bless u 2

hi omdano,
I do have older video 45mV (0.045volts) which was using Japanese transistor.Do refer to my youtube "sanjev21".I think it self run on 0.2volts,it's been a long time.That video is considered obsolete now.

[conradelektro]

Based on magpwr's work, the circuit on the attached drawing is the best I could do. It was already published in this thread way up. (As I said, it is magpwr's circuit, I just replicated.)

On the drawing I state the power consumption at several supply Voltages starting at 50 mV. Putting 500 mV into the circuit is already too much.

E.g. at 50 mV: if the Peltier element can not deliver 2.2 mA, it will not work (Voltage will drop below 50 mV).

If you provide a higher supply Voltage (e.g. 200 mV) the Voltage will drop till at least 2.2 mA are delivered.

The 2SK170 seems to be the only transistor easily available which can do that. Best to use 4 in parallel because the transistor has a resistance of ~200 Ohm (between drain and source) when open. Look up the specs of the 2SK170, it is an amazing transistor for very low Voltage and low power applications.

Your 200 mV (even the 100 mV from one of your Peltier elements) is plenty, as long as at least 2.2 mA are provided. I had to buy a 50 mm x 50 mm Peltier element, the smaller area Peltier elements delivered too little current when touched. (If you fire the Peltier element up with a flame and provide good cooling on the other side you get Amperes. The low temperature gradient between a human hand and ambient air needs a big Peltier area to give useful current.)

You might know that Peltier elements are not efficient, they only convert about 4% of the heat energy into electricity. Therefore you need a 200° temperature gradient, lots of heat and good cooling to get Ampere out of it. Whatever heat you can provide from human skin (best the warm hand) will result in very very little electricity. The 2SK170 is that very rare transistor which can still operate on the low Voltage (down to 50 mV) and the low Amperage (down to 2.2 mA).

On the photo you see a pan underneath my 50 mm x 50 mm Peltier element. Before I took the photo I put the pan outside in winter to cool it down to o°. This gave a temperature gradient of 30° (hand to 0° pan) for a minute and the LED was bright (and my hand was cold).

If you want to harvest heat from a human body you have to cover the whole body with Peltier elements and soon the person would shiver (if the outside is cold) or would heat up (if the outside is warmer).

Lately I bought this dynamo flashlight http://www.werbeartikel-discount.com/product_info.php/products_id/30608 and it beats everything I ever had in the field of alternative electricity production. An age old technology made useful with modern components. The human hand can provide a lot of mechanical energy without you even noticing it. I became a believer in the hand dynamo or the home trainer dynamo (which can deliver 40 Watt). Very simple technology which will not break easily.

Greetings, Conrad

[TinselKoala]

Futurlec has them for 20 cents apiece, 16 dollars US for a hundred.

http://www.futurlec.com/Transistors/2SK170pr.shtml

[omdano]

Which of the sellers have the fastest delivery service ? i want to get the 2SK170 in 17 days , thats what i am worried about (BTW i am middle eastern living in Dubai) the problem is the Shipment time always .

Thanks for all the help 

[MarkE]

I don't know what customs delays are like where you are.  These are commonly available commodity transistors.   If they are not available on the Peninsula then you should be able to obtain them without difficulty and a few days postal delay from:  Europe, India, or Asia.  A roughly equivalent part is an NTE132.  Or you can order those from Radio Shack on the web.