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Author Topic: Joule Thief  (Read 6275696 times)

stprue

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Re: Jule Thief
« Reply #15945 on: December 29, 2012, 06:44:34 PM »
Hello again E.

It's great to hear from you.  I'm sorry for your loss, but glad you will be back soon.

stprue

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Re: Jule Thief
« Reply #15946 on: December 29, 2012, 06:45:46 PM »
@all

Here is my latest ultra low power JT. 

P.S. Sorry for the low video quality.

http://www.youtube.com/watch?v=WlXKvnj-TuQ

conradelektro

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Re: Jule Thief
« Reply #15947 on: December 29, 2012, 07:02:15 PM »
@all

Here is my latest ultra low power JT. 

P.S. Sorry for the low video quality.

http://www.youtube.com/watch?v=WlXKvnj-TuQ

The best I could do was 1 Volt and 50 µA, see the attached circuit and photos. The LED glows always (no blinking).

@stprue: It would be nice to see a circuit diagram and component specification of your low power circuit.

Greetings, Conrad

P.S.: I found the circuit somewhere, not my invention.

crowclaw

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Re: Jule Thief
« Reply #15948 on: December 29, 2012, 11:28:06 PM »
@electricme
Still keep an eye on progress here,  may I say I'm  so sorry to here of your sad loss, God bless you Jim with better times to come in the New Year. Merv

electricme

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Re: Jule Thief
« Reply #15949 on: December 30, 2012, 04:51:44 AM »
@Wilby, stprue & croclaw,
Thank you all, it's appreceated very much.
stprue, the video looks fine by me, good work.
 

stprue

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Re: Jule Thief
« Reply #15950 on: December 30, 2012, 02:53:43 PM »
Hello Conrad,
I will hand draw a diagram and post it. 

@All
Someone here recently gave a link to a great little free circuit diagram program.  It also converted to breadboard views.  Does anyone know what the name of the program?

TinselKoala

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Re: Jule Thief
« Reply #15951 on: December 30, 2012, 03:09:22 PM »
I like the use of the magnets to make the battery connections, that's a nice touch and one that I will shamelessly start using in my lab.
Thanks!!

What happens if you remove the Schottky diode that is in series with the LED? I'm not grasping why this diode needs to be there.

kooler

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Re: Jule Thief
« Reply #15952 on: December 30, 2012, 04:07:03 PM »
@All
Someone here recently gave a link to a great little free circuit diagram program.  It also converted to breadboard views.  Does anyone know what the name of the program?

someone posted this one which is real nice..
http://fritzing.org/

conradelektro

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Re: Jule Thief
« Reply #15953 on: December 30, 2012, 04:46:01 PM »
I like the use of the magnets to make the battery connections, that's a nice touch and one that I will shamelessly start using in my lab.
Thanks!!

What happens if you remove the Schottky diode that is in series with the LED? I'm not grasping why this diode needs to be there.

I also use two little magnets, one has a red litz wire soldered to it and the other one a black litz wire. The other end of the wires has endings which plug nicely into the plus and minus rail of a breed board (solid wire ends soldered to flexible litz-wire). This gives an easy connection of a breed board to a battery. I saw this on a web site which discussed various circuits. Most things I know about electronics are gleened from some forums or web sites.

The Schottky diode in series with the LED turns the LED into a "good diode" which really blocks current in the reverse direction. In the forward direction it does no harm because its forward Voltage is lower than the forward Voltage of a LED. The power consumption of the 1 V 50 µA circuit I posted was lower when using the Schottky diode in series with the LED. I attributed this to the better reverse current blocking, but I could be wrong. The effect is not hight, may be some 20%.

I measured power consumption with a scope over a 1 Ohm shunt (in the positive power supply line) doing an approximate averageing of the Voltage curve by hand. The true RMS measurement of my scope over the shunt was pretty accurate as well (compared to the averageing of the Voltage curve by hand). The power comsumption of a Joule Thief happens in bursts. But my digital multimeter measured the power comsumption also very well (the average Voltage over a 1 Ohm shunt and the direct current measurement in µA when the multimeter was put in the positive power supply line).

I still believe (after many experiments) that a Joule Thief with an air coil can have less power demands in comparison to using a Ferrite toroid. But the air coil will be bigger than a Ferrite toroid. 100 turns for the base coil and 200 turns for the collector coil over a 2 cm plastic tube seem to be well suited for the circuit I posted. To keep the power supply voltage down to 0.5 Volt, the number of turns can be doubled. To start the Joule Thief I needed 0.7 Volt, but once started the Voltage could be dropped to 0.5 Volt. Air cores also allow for a higher frequency of oscillation which can reduce power demand when the currents become more like spikes.

A high electrolytic capacitor over the power supply (e.g. 100 µF) helps with weak power sources but increases the average power consumption. The reason seems to be that an electrolytic capacitor can give the peak power but a battery is to slow. So, when the peak power demand happens the electrolytic capaciter will fulfill it and then is slowly filled by the battery till the peak power demand happens again in the next cycle.

I am not so sure that a Joule Thief with two transistors uses less power in comparison to a one transistor JouleThief which is carefully designed (if one wants a LED that is continuously lit). The key features are frequency (should be 100 KHz or better more) and a very well designed coil, best air core. A 1 nF capacitor over a 100K to 500K resistor to the base helps to reduce power consumption by reducing the "switch on time" of the transistor and by assuring the necessary threshold voltage at the base to switch the transitor on.

I believe that power comsumption can be brought down to below 1 V and 50µA by having the LED blink, but this is not pretty according to my humble opinion.

White LEDs which I bought recently seem to need less power than red LEDs in order to be dimly visible. There was some progress concerning the light output of white LEDs.

I still try (without success so far) to have a LED continuously dimly lit by the electro smog in our environment (mobile phone transmissions, wireless LANs and 220 V 50 Hz mains grid). The energy density seems to be too low. A long antenna and a good ground seem to help, but still too little energy.

Greetings, Conrad

Pirate88179

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Re: Jule Thief
« Reply #15954 on: December 30, 2012, 06:00:18 PM »
Jim:

Great to see you back here Mate.  As you know, I too am very sorry for your loss.  Here's to better days ahead for all of us.  There is some great work being done here by many folks.  I have been unable to keep up with it all lately.  Lighting leds on such low power...it is amazing to me.

Happy New Year to you Jim, and to everyone.

Bill

stprue

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Re: Jule Thief
« Reply #15955 on: December 30, 2012, 06:33:39 PM »

someone posted this one which is real nice..
http://fritzing.org/

Yes this is the one I was looking for Kooler.

Thank you much!!!

TinselKoala

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Re: Jule Thief
« Reply #15956 on: December 30, 2012, 07:43:03 PM »
@conrad: thanks, the reason for the Schottky makes good sense, and I think I agree with all the rest of your post as well. I even got my JT test bed with basic JT circuit to work using the 40+40 turn bifilar air-core coil I wound just for the demonstration (connected as bifilar with the head-tail interconnect connected to the positive rail) , but it does use more current. I'm getting some very interesting effects with the modified Loopstick variable inductor w/ primary, but I haven't gotten around to videoing it yet.

Here's a circuit I found that seems very interesting and might be adapted to run an LED from the "electrosmog", but might need earth grounding.


conradelektro

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Re: Jule Thief
« Reply #15957 on: December 30, 2012, 08:07:59 PM »
Here's a circuit I found that seems very interesting and might be adapted to run an LED from the "electrosmog", but might need earth grounding.

@TinselKoala: thank you for the circuit which uses the mains humm as a power source. The full bridge rectifier seems to be the way to go. It could work in combination with the low Voltage Peltier Joule Thief circuit at http://www.overunity.com/13175/25mv-joule-thief-powered-by-peltier-merely-using-our-body-heat-free-energy-247/ . I ordered some 2SK170 transistors and will try.
 
In order to catch high frequency electro smog from mobile phone towers and WIFI spots one needs very high frequency diodes (8 GHz). I have some, but not being at home at the moment I can not look them up just now. Will post their specification some other day.
 
By the way, all AM radio transmitters have been shut down in Europe. Only some Eastern European countries like Russia still send some radio programs via AM. So, one has to go for FM (60 to 120 MHz), TV (400 to 800 MHz), cell phone transmissions (some GHz) and the WIFI and WLAN spots (up to 8GHz) or the 50 Hz humm from the 220V mains (which propably is the most promising).
 
Radar could be a power source (because all countries sweep their territory with Radar, and they reach up to a 1000 km radius overlapping each other. But the frequency is around 400 GHz or even higher. There are diodes for this frequency but they are not easily available on the market.
 
An other area is VLF or ELF (down to a frequency below 1 Hz). The military uses it for submarines and also lightning causes ELF transmissions. It needs very long antennas, but my garden fence could be the antenna. There still might be some surprises in the ELF range (http://en.wikipedia.org/wiki/Extremely_low_frequency) , it is not well researched. Nature might transmit something there which could be used as a powersource.

Greetings, Conrad

electricme

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Re: Jule Thief
« Reply #15958 on: December 31, 2012, 05:17:37 AM »
@Pirate
Thank you Bill....... I will B in touch shortly by land line
@TinselKola, I like your Crt drawing in the "air power" to run a something,,,,,, put a Super Cap on it's output and see if you can save it.
@Conradelectro, exactly, spot on about the caps.
Q... how do I cram 1,000,000 posts since I was here last? lol
@ Everyone, Happy new year to you all.
 
 

Lakes

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Re: Jule Thief
« Reply #15959 on: December 31, 2012, 10:35:13 AM »
Another circuit.
https://sites.google.com/site/amplificatoare/free-energy-collector-circuit.

@Tk like the circuit, I remember building something similar many years ago.

Happy 2013 everyone!