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

[scratchrobot]

I also got my 2SK170 transistors and finally it's working now
The led seems to start glowing around 35mv, will do some more testing with this nice circuit.
Thanks Magpwr and others for helping me getting started with this.

http://www.youtube.com/watch?v=bWqo4akFdVk

Regards,

[magpwr]

Hi,

Glad to know the circuit is working for you guys to validate my ultra low voltage joule thief claims.

Just to clarify the "25mV" i meant was the JFET base circuit starts to "self oscillate" it's not about lighting led at 25mV.

It's slighthy higher at around 50mV input for lighting white led.

[conradelektro]

50 mV is the best I can do. Coil ratio 10:100 seems to be marginally better than ratio 4:100. I see not much difference between using one or two 2SK170 transistors.

I did some tests with home made batteries and with a 50 x 50 mm Peltier Element. See the attached photos and the circuit diagram.

This Joule Thief circuit with the 2SK170 transistor does what I hoped it would do:

1) It works with just one cell of a home made battery. The two batteries I tested today each hold a Voltage of about 150 mV when connected to the circuit and the white LED glows nicely.

2) It also works with just one Peltier Element at a very moderate temperature differential. I had an aluminium plate at both sides of the Peltier Element. The cold side aluminium reached into cold tab water and the hot side aluminium was warmed up by hand. It also works without the cold water reservoir (the cold side at room temperature), but after some minutes the temperature of the cold side will warm up towards the temperature of the hand.

Will try with a different Toroid and with 4 transistors in parallel. In the coming days I also want to do tests with an air coil and some ALD110800 and ALD110900 transistors should arrive soon.

It might be necessary to change the circuit for the ALD110900 or ALD110800 because the Gate has a diode towards the negative rail in order to protect the transistor from a wrong potential between Gate and Source (Gate should not go below Source). But it might be possible to leave the diode pin unconnected (pin V- of the component left open)? We will see whether the component needs a connection to the negative rail? If not, the circuit can stay as it is.

Greetings, Conrad

[scratchrobot]

I used a small 10mm toroid 100:4 and there is not much difference when using 1 or 4 2SK170 transistors but with 4 the led glows a little better. I did a test in the dark and the led starts glowing at around 30ma input from the peltier. I made another video, the led is above the multimeter. http://www.youtube.com/watch?v=ak-aFHztZLg

[conradelektro]

I used a small 10mm toroid 100:4 and there is not much difference when using 1 or 4 2SK170 transistors but with 4 the led glows a little better. I did a test in the dark and the led starts glowing at around 30ma input from the peltier. I made another video, the led is above the multimeter. http://www.youtube.com/watch?v=ak-aFHztZLg

@scratchrobot: following your idea and video of doing a test in the dark, I see a very faint glow in the white LED at 36 mV (using the Peltier Element as shown in the photo in may last post). Because my DMM is not a top quality instrument, let's say it happens at 40 mV. (Circuit shown in my last post.)

I am impressed by the 2SK170 transistor, it seems to allow oscillation at very low Voltages (which I even can not measure with my instruments). It already oscillates well below the Voltage at which the LED starts to glow.

I am very happy that all seems to work very well at 100 mV (LED sufficiently bright to impress onlookers), which is good enough for most home made very simple battery cells and for simple Peltier experiments with body warmth and ambient temperature.

I plan a "coffee or tea cup temperature indicator" on top of which one places a hot or warm cup or mug and the gadget inicates whether it is till warmer than room temperature by the glowing LED. Not realy a world saving invention, but it could serve as a novelty item for science geeks.

Tomorrow I will test an earth battery  in the garden (copper and aluminium tube driven into the ground in close proximity).


@magpqr: thank you for clearyfying the 25 mV result, I thought I did something wrong because my white LED only started to shine at 50 mV. With a good Voltmeter (very high impedance) one could may be see oscillation with a 2SK170 at even lower Voltages than 25 mV.

Greetings, Conrad