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Author Topic: Joule theif not working at 0.5 v ?  (Read 19176 times)

Offline omdano

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Joule theif not working at 0.5 v ?
« on: January 27, 2014, 09:47:29 PM »
Hello , I have made a joule thief using the guide from MAKE channel about it the link is :
http://www.youtube.com/watch?v=gTAqGKt64WM

so... i used a 2N2222 transistor

And it lighted the led with a 1.5v battery (yea... 1.44 but yeah)

then i used a 0.5v battery but didn't work
Even tho it is told that it will work till 0.3v

What happened?
and how can i fix it ?

Free Energy | searching for free energy and discussing free energy

Joule theif not working at 0.5 v ?
« on: January 27, 2014, 09:47:29 PM »

Offline wings

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Re: Joule theif not working at 0.5 v ?
« Reply #1 on: January 27, 2014, 10:23:26 PM »
Hello , I have made a joule thief using the guide from MAKE channel about it the link is :
http://www.youtube.com/watch?v=gTAqGKt64WM

so... i used a 2N2222 transistor

And it lighted the led with a 1.5v battery (yea... 1.44 but yeah)

then i used a 0.5v battery but didn't work
Even tho it is told that it will work till 0.3v

What happened?
and how can i fix it ?
basically a .6v to .7v is required for a silicon transistor , 0.3 for germanium


Offline MarkE

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Re: Joule theif not working at 0.5 v ?
« Reply #2 on: January 27, 2014, 10:45:20 PM »
Hello , I have made a joule thief using the guide from MAKE channel about it the link is :
http://www.youtube.com/watch?v=gTAqGKt64WM

so... i used a 2N2222 transistor

And it lighted the led with a 1.5v battery (yea... 1.44 but yeah)

then i used a 0.5v battery but didn't work
Even tho it is told that it will work till 0.3v

What happened?
and how can i fix it ?
Use a lower voltage transistor.  JFETs are ideal, Ge transistors will at least get you closer to zero.  If you use junction transistors, heating the transistor up will lower the starting voltage.  You could use that to invent the "match lite Joule Thief".

Offline conradelektro

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Re: Joule theif not working at 0.5 v ?
« Reply #3 on: January 27, 2014, 10:53:49 PM »
This must be the fifth time that this issue comes up.

Attached is a circuit with 4 transistors 2SK170 in parallel which will work down to 50 mV (at about 2 mA).

It was first published by magpwr some time ago.

Greetings, Conrad


Offline xee2

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Re: Joule theif not working at 0.5 v ?
« Reply #4 on: January 28, 2014, 03:54:40 AM »

then i used a 0.5v battery but didn't work
Even tho it is told that it will work till 0.3v

What happened?
and how can i fix it ?


A silicon transistor Joule thief will often work at 0.4 volts if the voltage is slowly decreased while it is running. But will not generally not start at 0.4 volts.

Free Energy | searching for free energy and discussing free energy

Re: Joule theif not working at 0.5 v ?
« Reply #4 on: January 28, 2014, 03:54:40 AM »
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Offline omdano

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Re: Joule theif not working at 0.5 v ?
« Reply #5 on: January 28, 2014, 01:17:13 PM »
Use a lower voltage transistor.  JFETs are ideal, Ge transistors will at least get you closer to zero.  If you use junction transistors, heating the transistor up will lower the starting voltage.  You could use that to invent the "match lite Joule Thief".

So... any JFET ? would you recommend any types or any specific ones ? (Except 2sk170 / LSK170 )

Offline conradelektro

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Re: Joule theif not working at 0.5 v ?
« Reply #6 on: January 28, 2014, 02:25:11 PM »
So... any JFET ? would you recommend any types or any specific ones ? (Except 2sk170 / LSK170 )

Sorry, many people tried to find a replacement for the 2SK170, all transistors found were worse. In practice there are hardly any applications for a circuit below 0.5 Volt. To do anything useful below 0.5 Volt the current has to be very high. In general it is better to have a higher Voltage (at least 1 V or 3 V) and less current because the components do not heat up so much.

I did some tests with the transistor ALD110900, but it is much worse than the 2SK170 and more expensive (see the attached circuit).

So, if you want a transistor that switches down to 50 mV, I am afraid you have to get the 2SK170. I know, it has become difficult to get, try eBay.

http://www.ebay.com/itm/2SK170-TOSHIBA-FET-Transistor-N-Channel-QUAD-MATCH-4PCS-/270914931710?pt=LH_DefaultDomain_0&hash=item3f13c9cbfe
http://www.ebay.com/itm/2SK170-GR-Toshiba-JFET-Transistors-/300881599819?pt=LH_DefaultDomain_0&var=&hash=item460df0dd4b

Greetings, Conrad

Free Energy | searching for free energy and discussing free energy

Re: Joule theif not working at 0.5 v ?
« Reply #6 on: January 28, 2014, 02:25:11 PM »
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Offline omdano

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Re: Joule theif not working at 0.5 v ?
« Reply #7 on: January 28, 2014, 02:29:07 PM »
Guys , i am not talking about 50mV i am talking about 0.5 volts as in 500mV

Offline conradelektro

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Re: Joule theif not working at 0.5 v ?
« Reply #8 on: January 28, 2014, 02:35:47 PM »
Guys , i am not talking about 50mV i am talking about 0.5 volts as in 500mV

Then use the ALD110900 or ALD110800 it works down to 0.2 Volt (200 mV).

http://at.mouser.com/Search/Refine.aspx?Keyword=ALD110900

http://at.mouser.com/Search/Refine.aspx?Keyword=ALD110800

Still, I would go for the 2SK170 because it leaves room to go far below 0.5 Volt. If you are at this low Voltages, how long will it take before you go down from 0.5 Volt?

There is no easy way, you would not be here to ask if there was. We do not do miracles.

Greetings, Conrad

Offline omdano

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Re: Joule theif not working at 0.5 v ?
« Reply #9 on: January 28, 2014, 02:42:01 PM »
I am not using a battery for this one , i am going to use a constant 0.5 v power supply of my own

Free Energy | searching for free energy and discussing free energy

Re: Joule theif not working at 0.5 v ?
« Reply #9 on: January 28, 2014, 02:42:01 PM »
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Offline TinselKoala

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Re: Joule theif not working at 0.5 v ?
« Reply #10 on: January 28, 2014, 04:19:57 PM »
Sorry, many people tried to find a replacement for the 2SK170, all transistors found were worse. In practice there are hardly any applications for a circuit below 0.5 Volt. To do anything useful below 0.5 Volt the current has to be very high. In general it is better to have a higher Voltage (at least 1 V or 3 V) and less current because the components do not heat up so much.

I did some tests with the transistor ALD110900, but it is much worse than the 2SK170 and more expensive (see the attached circuit).

So, if you want a transistor that switches down to 50 mV, I am afraid you have to get the 2SK170. I know, it has become difficult to get, try eBay.

http://www.ebay.com/itm/2SK170-TOSHIBA-FET-Transistor-N-Channel-QUAD-MATCH-4PCS-/270914931710?pt=LH_DefaultDomain_0&hash=item3f13c9cbfe
http://www.ebay.com/itm/2SK170-GR-Toshiba-JFET-Transistors-/300881599819?pt=LH_DefaultDomain_0&var=&hash=item460df0dd4b

Greetings, Conrad

I don't know why people think that the 2sk170 is "difficult to get". There are lots of advertisers with lots of stock, genuine Toshiba stock too. Prices I've seen vary from very low like 20 cents each to very high, like several dollars for a matched pair. You can get lots of 10,000 in original Toshiba packaging from EBay. Or you can get individual ones without Toshiba branding for 20 cents each.

http://www.futurlec.com/Transistors/2SK170pr.shtml


I've got one JT here, the DALM circuit with four blue LEDs _in series_, that oscillates (without lighting the LEDs) down to around 360 mV, but needs about 610 mV to actually light the LEDs. It uses a BC337-25 or a MPSA18 silicon BJT and has a 1:1 toroid winding ratio. (20+20 turns).

Offline TinselKoala

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Re: Joule theif not working at 0.5 v ?
« Reply #11 on: January 28, 2014, 04:32:54 PM »
I have a handful of 2n5163 FET transistors that I pulled from some surplus MRI scanner boards. I haven't tried one in a JT yet but according to the data sheets they might work nearly as well as 2sk170.

Has anyone tried the 2n5163 yet?

 


Offline omdano

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Re: Joule theif not working at 0.5 v ?
« Reply #12 on: January 28, 2014, 04:49:12 PM »
What about the all forgotten germanium transistors ?
don't they work as low as 0.2v ?

Offline conradelektro

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Re: Joule theif not working at 0.5 v ?
« Reply #13 on: January 28, 2014, 07:38:10 PM »
What about the all forgotten germanium transistors ?
don't they work as low as 0.2v ?

Look at that search http://at.mouser.com/Search/Refine.aspx?Keyword=germanium+transistor and you will see that the modern germanium transistors are optimised for high frequency (GHz) not super low Voltage.

0.5 V seems to be a little bit too low for making a LED light up with a Joule Thiefe type circuit, unless you find something like the 2SK170, and the only one coming close some one found is the ALD110900.

There are older Japanese transistors, but they are realy hard to get.

I would say you put your "constant 0.5 V power supply of your own to 0.7 V" and you are out of trouble, almost any transistor will work.

There is a post by magpwr which describes the found transistors, but they are not available any more:

http://www.overunity.com/13175/25mv-joule-thief-powered-by-peltier-merely-using-our-body-heat-free-energy-247/msg350815/#msg350815

You can go through that thread (only 11 pages) to see yourselfe what has been done then.

Greetings, Conrad


Offline Vladokv

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Re: Joule theif not working at 0.5 v ?
« Reply #14 on: January 28, 2014, 11:00:08 PM »
The germanium transistors work at 0,2V flat. At that voltage led is not very bright. I will tomorow post pictures. One strange thing also ocurs - joule tief with germanium transistor don't work at 1,4 - 1,5v, don't know why. Work with more and less but not with 1,5v exactly

Free Energy | searching for free energy and discussing free energy

Re: Joule theif not working at 0.5 v ?
« Reply #14 on: January 28, 2014, 11:00:08 PM »

 

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