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

[conradelektro]

TinselKoala did some tests with the 2SK170 Joule Thief circuit, see http://www.youtube.com/watch?v=OgndINJHnd0 and http://www.youtube.com/watch?v=35IMWNp2akg

I put the circuit together again and did some scope measurements:

- the power supply was set to about 100 mV (I used only one 2SK170, if one puts 2 or 4 in parallel the supply Voltage can go down to 50 mV)

- note that the 2SK170 has a high resistance when switched through (at least 100 Ohm), the primary winding is therefore never pulled completly to GND

- if one measures over the "LED and the diode" (scope CH 2, at the base resitor) one sees that the LED is switched off and on

- if one measures only over the LED (scope CH 2a) a "ripple current" seems to show up, but this is an artifact because the diode is blocking the scope probe from going more positive

- the supply Voltage should not be higher than 500 mV, the current through the transistor (drain to source) would be too much

- the circuit swings at about 30 KHz, but a scope probe (indicated as CH 2 in the circuit) at the base resistor changes the frequency to about 25 KHz

- if the Toroid has less inductance the frequency will be higher but the supply Voltage has to be higher too (may be 200 mV)

Greetings, Conrad

[TinselKoala]

Yes, exactly. That 2a trace is the one. You say this is an artifact caused by the diode, but surely the scope probe is seeing the same thing the LED is seeing on that side of the diode. It looks to me like the LED must be just barely flickering, around its fwd voltage point, dimming and brightening in time to the "ripples" on that signal. I haven't had the time to explore it with a photoresistor to see what the light from the LED is actually doing yet, I got distracted by another project.

You've motivated me to rewind that tiny ferrite bead, though, to see if I can get a lower operating voltage. I think I can get 100 turns onto it, but the wire keeps breaking (it's scrounged wire from a TV yoke).

Since the video, I've put a 1n5711 Schottky diode in place of the 1n34a. It got me a few more millivolts lower but not much. Down at the bottom of this page there is some interesting info on detector diodes.
http://www.techlib.com/electronics/crystal.html

[iii_WARHEAD_iii]

Finally I have found time to assemble suggested circuit from this thread
https://www.youtube.com/watch?v=ozQwneBTRB0

Start up operation voltage 24-25mv with coil from Coilcraft 1:20
Vin ~ 0.076V -> Vout ~ 3.12V
Iin   ~ 1.6mA -> Iout  ~ 0.14ma
Possible to start from 14mv with 1:50, but Vout will be only ~1.4V
Resistance of secondary coil in 1:50 twice bigger than in 1:20
By tuning resistor it is possible to get higher output voltage in addition around 100-200mv, which is enough to compensate hysteresis from second circuit

Second circuit contain Voltage detector BD4930. Due to internal hysteresis Vdet*0.05, LED blinks with 100% power only at V=3.12V. And Tantalum capacitors 470uF and 4.7uF
and I have to replace diode (from graphic card, protective diodes), otherwise I lose 0.7V on it.

What do you think about these transistors, some of them complete analogue of SK170, another have twice bigger conductivity
CPH6904-TL-E    http://de.rs-online.com/web/p/transistoren-jfet/7919403/
2SK2394-7-TB-E http://de.rs-online.com/web/p/transistoren-jfet/7925155/
2SK3557-7-TB-E http://de.rs-online.com/web/p/transistoren-jfet/7925167/
CPH5905G-TL-E  http://de.rs-online.com/web/p/transistoren-jfet/7925278/
TF252-4-TL-H      http://de.rs-online.com/web/p/transistoren-jfet/7919594/

[abtahee16]

Can I study with this brightness of light?

[Ruturaj]

Hi
I am making a thermoelectric flashlight which works completely from the heat of our hand.I am using a peltier module(TEC1-12706) which is cooled by water.So,can anyone suggest an efficient,working circuit for me please.