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

[conradelektro]

@magpwr: thank you, great list, that helps a lot.

I guess you wrote "mV" where it should be "V", see this list which I will keep for reference:

N channel JFET which could self start at low voltage <100mV (according to magpwr):

2N4861A   0.35 V     start up
2N4393     0.060 V   start up  with BD329
2N3972     0.033 V   start up    *********** Could self start at 22mV (or 1mV lower than 2SK170)but much lower current output capability
2SK117     0.031 V  start up - high current output

2SK170      0.030 V  start up - high current output  ******final testing reveal this is the best self starting at 23mV

2SK364      0.031 V  start up - high current output
2SK366      0.031 V  start up - high current output

2N4093       0.35 V    start up
2N4223       0.35 V    start up
2N5484       0.060 V  start up
2N5103       0.060 V  start up

BF510          0.045 V  start up
BF410B        0.060 V

BC264C        0.060 V
BC264A        0.060 V
BC264D        0.060 V

Magpwr please verify, this list is very helpful for everybody playing with Joule Thief type circuits. I will put it into a spread sheet once verified by you.

I do not understand "2N4393     0.060 V   start up with BD329" (how is it started with the BD329)?

Mouser sells the 2SK3666-2-TB-E and the STD35N3LH5. Are they replacements for the 2SK364 and 2SK366?
Mouser also sells 512-MMBF5103, a replacement of BF510?
Mouser sells the 771-BF510215 , a replacement of BF510?

The 2SK170 is fairly easy to get, all the other are not widely sold.

Sorry to ask again about the ZTX1048: I understood that one could start the ZTX1048 with a 2SK170, but at what Voltage would the ZTX1048 start alone (just the ZTX1048), at 40 mV ?

Greetings, Conrad

[conradelektro]

Some results with 4 transistors 2SK170 in parallel in magpwr's circuit: 2.2 K resistor in front of the Gate (magpwr specified 1.8 K), 2N5711 diode in series with a white LED.

The white Led starts to glow at 37 mV and is clearly visible at 50 mV.

Power usage is rather high, that is why the LED glows stronger with 4 transistors in parallel:

2.2 mA at 50 mV
6 mA at 100 mV
14 ma at 200 mV (LED is very bright at 200 mV)
34 mA at 500 mV (this is too high, needs a 10 K resistor at the Gate to reduce current to 20 mA)
(do not try with 1 Volt, could destroy the transistors)

It works fine with a 50 mm x 50 mm Peltier Element: cold side at room temperature (about 22 degrees Celsius) and the hot side touched with the hand. Again I see that the LED starts to glow around 37 mV and is nicely visible at 50 mV which is reached within seconds when touching the Peltier Elemet with the hand.

I could also make a LED shine with 4 transistors 2SK170 in parallel and the Slayer Exciter circuit I showed in this thread. But it needs at least 100 mV to make the LED glow, so magpwr's circuit is better.

In case one wants to use 1.5 Volt batteries (till they are deeply discharged down to 200 mV) one could use the ALD110900 transistor in the Slayer Exciter circuit I showed earlier in this thread because it does not need any additional components (just the toroid with the windings and the white LED) and uses very little power (1 mA at 1 V).

But for a really low Voltage power supply (50 mV to 200 mV) magpwr's circuit with four 2SK170 transistors in parallel is great. It needs a few mA to work, about 100 µW at 50 mV, and it is astonishing  that one can make a LED glow with such little power and such little Voltage. With one 2SK170 transistor the demand is only 500µA in order to see the LED dimly glow at 50 mV.

Greetings, Conrad

[magpwr]

hi Conradelektro,


I have admended the voltage in earlier posting(hours ago) eg:0.035mV changed to 35mV.


The one which i combine JFET with BD329 was at early stages of testing.Could ignore those old value which i forgot to remove as ZTX1048A combine with 2SK170 in parallel configuration using 1 resistor 2.2kOhms from secondary coil still produce better result at higher current draw.This could be the version 2.0 circuit maybe not suitable for peltier.I  noticed  peltier raw output is around 10mA for me with 6c temperature difference.


ZTX1048A(4amps direct,20A pulsing for one tiny transistor with no heatsink ,refer to datasheet) could self start at usual around 0.6volts like all silicon transistor.But voltage drop across emitter and collector at below 200mA is around 50mV base on datasheet ,VCE drop across common average transistor is around 0.3...0.5v .
ZTX1047A should be slighter better but i can't find those online.

[gyulasun]

Hi Folks,

I have made some comparison on JFETs as per electrical data and I think the BF861B from NXP (earlier Philips type) may be worth a test because most of its features are the same or  a bit better than that of the 2SK170. Here is a data sheet for it:
http://www.nxp.com/documents/data_sheet/BF861A_BF861B_BF861C.pdf  and Farnell has it http://uk.farnell.com/nxp/bf861b-215/jet-n-ch-25v-sot-23/dp/1758057 
The highest transconductance of this family is BF861C but it should be looked for where it is avalable  EDIT RS Components seem to have it http://uk.rs-online.com/web/c/?searchTerm=bf861&sra=oss&r=t  a package of 10 should be ordered...

I do not know this seller but they seem to sell ZTX1047A: http://elcodis.com/searchparts/ztx1047.html   Farnell and others has the ZTX1048A.

rgds,  Gyula

[conradelektro]

@gyulasun: thank you for searching the BF861B, since it is not expensive I might order it.
@magpwr: thank you for updating the transistor list.

I looked for the transistors named by magpwr and found the following sources:


2SK364 (31mv start up -high current output)  511-STD35N3LH5  Mouser (might not be the same, replacement type)

2SK366 (31mv start up -high current output)  863-2SK3666-2-TB-E  Mouser

BF510   (45mv start up)  512-MMBF5103  or  771-BF510215  Mouser

2SK170 (30 mV start up - high current output, best so far)  Mouser,  Reichelt (Germany),  eBay seller diy-audio4you (Germany)

ZTX1048A (600 mV startup, combine with 2SK170)  522-ZTX1048A  Mouser,  Farnell

BF861B (not tested, Gyulasun)  Mouser,  Farnell


I attached a photo of my Peltier Element Test (4 transistors 2SK170 in parallel, steel cooking pan at room temperature about 22° Celsius, Peltier Element 50 mm x 50 mm).

Greetings, Conrad