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

[magpwr]

Hi conradelektro,

Nice work man.This is how 1st started with <100mV Joule Thief using transistor 2SD1450 (0.13v..0.3v VCE(voltage drop between emitter and collector at 400mA.By referring to datasheet and looking at vce
for expected circuit current draw.

If you refer to my youtube channel  "sanjev21" "45mV Joule Thief" was my 1st low power joule thief  using  "2SD1450" Japanese transistor.But it was not self starting and i had to manually short emitter and collector of transistor to kick start oscillation.

My other experiment which i have not posted in youtube using the best NPN transistor i could find in digikey "ZTX1048A" which have the lowest Voltage drop across emitter&collector at mere(27mV...45mV) at 500mA.Little smaller than TO92 and could handle 4Amps or 20Amps pulse no "heat sink".
Using this ultra low drop transistor i could achieve oscillation as low as "30mV" but as usual i have to kickstart oscillation at higher voltage eg:60mV by temporary shorting emitter&collector.

I have also combine ZTX1048A transistor(To boost output current) and (2SK170 or 2SK364 or 3SK366 .But take note 2SK170 do have better lower starting voltage by 1..3mV)  Junction-FET(To self start osc at low voltage).Connecting 22ohms from coil to transistor and 1.8k coil to JFET Gate while connecting (JFET Source to transistor emitter,J-FET Drain to transistor Collector).Design for <100mV.

For this above transistor and JFET combined circuit i was able to charge 1000uf cap in matter of <5sec to reach around 2volts.

But the current drain for above transistor with JFET circuit  is  around 100mA .
I was using 50FARAD 2.5v Ultra capacitor(charged with 1AA battery for few seconds to reach 100mV) as power source.Since it's known ultra cap got very low internal resistance.

The above circuit will work very nice on 1.5V battery but need to tweak 22ohms resistor to higher value to maintain current draw at decent level eg:100mA.
Then again i realised it's pointless using JFET for 1.5v battery since we could use transistor which is more efficient at higher current.

Peltier only produce <5mA if I connected to multimeter if i use my hand as heat source(36.5c) against room temperature in my case(30c for a hot country) 6.5C difference.
The peltier i'm using do have internal resistance of around 3ohms(Out of the box /Not in use).
In theory i'd believe if we use lower internal resistance for peltier <2ohms we may get better current output but then again.I 'm not sure if multi meter could properly detect "current" at such low voltage produce from peltier 70mV..90mV.

Solar cell do work to power my JFET base joule thief in room lighting or led light.I'm not sure if using other power source like from crystal radio could work.

If we match "source and circuit impedance" then we could  further optimize on efficiency.


Lastly the circuit do work on 1 x 2SK170 as well with lower Circuit current draw at 1mA using peltier at around 60mV. I used 4 JFET  since i noticed there is improvement with output voltage especially with Led as load current draw increases to 4.2mA(Mentioned in youtube description).

Lastly if anyone wish to go for extreme low starting voltage at 22mV instead of 25mV got to try 2n3972 JFET (But very low current handling in itself output capacitor cannot be more than 100nf) and combine with 2SK170 x 3 or 4.

If anyone is a expert with SMD base tiny circuits there is UK base company which manufacture 2SK170 as LSK170  (TO92 package and SMD tiny version).
http://www.micross.com/packaged-parts-plastic-discretes.aspx

[conradelektro]

@magpwr:

I just realised that I can start oscillation of your circuit with a 2N3904 transistor at 0.2 Volt by briefly shorting collector / emitter.

I found a source for the 2SK170 transistor in Germany

http://www.reichelt.de/

and I would be able to get the ZTX1048A transistor from Farnell.

At what Voltage does the ZTX1048A self start? (You mentioned that you could start it at 60 mV by briefly shorting collector / emitter.)

I did not find a source for the 2n3972?

There should be a replacement for the 2SK170, but I did not find any?

Greetings, Conrad

[TinselKoala]

http://www.utsource.net/ic-datasheet/2N3972-677148.html
9 dollars US !!

http://www.utsource.net/ic-datasheet/2SK170-1553154.html
2 dollars.

I've made 2 orders with these people, for mosfets and strange transistors for my F43 FG.... the ordering is painless and the shipping for small quantities is only 4 dollars, but it takes 7-10 business days for the parts to arrive. The parts I ordered were cheaper here than anywhere else for small quantities, and they have stuff that nobody else seems to have, like the Motorola transistors I needed.

[conradelektro]

I did some power consumption measurements:

Magpwr's circuit as shown in myReply #29 with a 2N3904 transistor uses about 1 mA at 0.2 Volt, which is about 200 µW. The white LED glows dimly.

This is the lowest supply Voltage I personally could ever achieve, but it has to be started by briefly shorting collector / emitter. But I could achieve 50 µW with a 1 Volt power supply with an other circuit, see my Reply #15947 at http://www.overunity.com/6123/jule-thief/15945/#.UOcYyne7kaw (Jule Thief thread page 1064).

I am really looking forward to test the 2SK170 transistor. A self starting Joule Thief type circuit with a power supply of less than 0.1 Volt (even if it needs 1 mA) would be really good for my self made batteries (salt water as electrolyte, silver coated copper wire or graphite chunk versus magnesium chunk or aluminium plate or galvanised steel plate) or for Peltier Elements. Magpwr has shown it and I hardly can wait to see it myself. And I have to try air cores with the 2SK170.

It is of course of little use to dimly light a LED, but it is a nice experiment to make a tiny amount of power visible in the form of a glowing LED.

I never observed OU with a Joule Thief type circuit but one can do amazing stuff like High Voltage at high frequency (Slayer Exciter type circuits, which I like to call modern Tesla Coil Towers), or strong 110V or 220V LED lamps (LaserSabers Joule Ringer) and many other variants all showing some interesting features. Just a few components and so many possibilities.

For me the nice thing about the Joule Thief type circuits is that they work, the LED or the lamp lights up, instant gratification. An other "field" that works for me are the pulse motors (also not OU, but they really spin).

@TinselKoala: thank you for mentioning utsource.net, it is always interesting to know where to get stuff.

Greetings, Conrad

[scratchrobot]

Hi Scratchrobot,

I'm sorry you had to find out the hard way.I did mentioned somehwhere in youtube description or comment to another interested person whom wish to construct the ultra low voltage circuit.
Never to try any Jxxx series all those don't work.I have done stimulation testing using trial software to find out the best component(It's on you to find out.I won't reveal it).
Please don't bother trying other Junction FETs you won't get ultra low self startup voltage.I have wasted 3 days to accidently discover a self starting joule thief at below <30mV while trying to optimise joule Thief.

I bought 2SK170 from  http://www.futurlec.com  (After searching in internet high and low) for $0.20ea (Bought 10 pieces for $2 USD) Since i'm living in Asia shipment is only around $5.50USD for me.Got it within  2 weeks.

Recent discovery my circuit could be powered by solar cell in room merely shine a led torchlight to part of the 1.7v solar cell(400mA) to light a led again from my ultra low joule thief(NOT OVERUNITY).

No problem, i'm used to learn the hard way 
I just ordered some 2SK170 from http://www.reichelt.de/ thanks Conradelektro for the link.
So I will try your circuit again when they arrive.

Keep up the good work.