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Making A Simple Joule Thief (made easy)

Making A Simple Joule Thief (made easy)
Today I am showing you how to make a very simple joule thief. A joule thief has many applications, the best gadget that I made with was a "Water Powered Lamp", soon I'm going to post on a guide about it but first I need to post this guide. I used an iPhone 4S as my camera :))) 

What Is A Joule Thief ?

To simplify everything, a "joule thief" is a circuit that helps drive an LED light even though your power supply is low. What can we do with it? We can use it to squeeze the life out of our old, almost drained, non functioning batteries. This project can also be considered as a green and environmental experiment, we can also use it as a flashlight that can be ran by an old, weak, almost drained battery. I even tried to use my water powered battery from my previous instructable the "Water Powered Calculator", the project was featured and displayed in instructable's front page in the "Technologies" category.

My Next Projects That Involves A Joule Thief: (soon to be posted)
- Water Powered Lamp
- Water Powered Flash Light
- Dead Battery Drainer Lamp

 

Here's A Video From Make Magazine:




 
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Step 1Parts And Materials

Parts And Materials

The Parts Needed Are: (click the item to know where to find/ buy)

- Round Ferrite Toroid (can be found in old CFL bulbs)
- Old/ Used Batteries (can be found in garbage cans)
- NPN Transistor (2N3904)
- 1K Resistor (BRN-BLK-RED)
- LED Light
- Battery Tester (optional)
- Soldering Lead
- Copper Wire/ Magnet Wire
- Battery Case/ Holder

I want to share something. Here in the Philippines electronic parts are extremely cheap, they are extremely far cheaper from
radio shack, for example one transistor costs (2 phil. pesos - 6 US cents), a LED cost (9 phil. peso -  29 US cents) and a 1K resistor cost (25 phil. cents - 0.8 US cents). I usually buy thing from Deeco or Alexan. Usually prices here are 15x cheaper from radio shack. Price conversion - $1 US Dollar = P0.31 Philippine Peso (12/24/11). 
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100 comments
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Dec 24, 2011. 2:20 PMoanderson says:
Nice Instructable, very useful for the novices out there and the more advanced tinkerers! I see your next project is a lamp, I check this one out: http://www.instructables.com/id/Table-top-energy-seed/ I'm thinking of making one :)
Jan 1, 2012. 4:39 PMproject_builder says:
great project! Always wondering what to do with the old batteries i had laying around. im glad im not the only 13 year old doing projects like this. Try my 12 volt varyable power supply project! Thanks!
Jan 2, 2012. 7:12 AMricharno says:
You got my vote!
Thanks for this nice instructable.
Jan 2, 2012. 12:49 PMgrimdaddy says:
I am not a electronics guy and I have a few questions.
1:What happens if you hook this up to a new battery?
2: What happens if you hook it up to a three volt cell?
3:Could this be adapted to a 1watt Led that runs on six volts?
4: Could this be adapted to a flashlight, more specifically a tactical flashlight?
This looks like an idea that could go places.
Jan 3, 2012. 4:47 PMvmars316 says:
Very cool project.
I am just learning about electronics:
could this same 'circuit type' be used for a
"free energy" from radio waves project?
Could someone, more qualified than me, design such a circuit?
Thanks...Vernon
May 21, 2012. 3:24 AMVishal Singh led says:
coolest thing
to make
May 4, 2012. 12:44 AMUtsav25 says:
Can I add a capacitor or another transistor somewhere to increase the output power so that the LED glows more brightly?
May 4, 2012. 8:38 AMUtsav25 says:
OK. I'll try it out .Do you have a schematic that you can provide?
May 2, 2012. 9:44 AMUtsav25 says:
Very nice project works great .!
Mar 17, 2012. 12:50 AMdash24 says:
is it ok to used an any kind general purpose npn transistor instead of what you used there?
Mar 10, 2012. 7:50 PMGoodwin7 says:
Nice instructable, I find it helpful, thanks!
Feb 26, 2012. 6:25 PMnerj says:
Good instructable's for all enthusiast, keep it up.
Feb 11, 2012. 7:39 PMknexbuilder88 says:
For my joule thief, can i use zinc wire instead of copper? Is there a difference in performance if zinc wire is used?
Feb 14, 2012. 5:33 PMknexbuilder88 says:
oh good,that was all i had laying around:)
Feb 4, 2012. 8:48 AMproject_builder says:
does it matter what npn transister you use?
Feb 4, 2012. 9:33 AMJordan Dyck says:
hmm? i'm thinking my transistors dead
Dec 30, 2011. 8:28 AMactivenowhere says:
Can you link to a place selling suitable toroid? Taking apart a CFL really isn't the best option for me.
Jan 2, 2012. 10:44 AMCanoeman says:
Any ham radio store or electronics shop should carry a wide spectrum of toroidial cores.
Jan 30, 2012. 5:08 AMacmefixer says:
The toroids for radio frequency and ham use have too low permeability and need too many turns of wire. The much higher permeability toroid cores found in switching power supplies and CFL lamps are much better for a Joule Thief.
Jan 31, 2012. 5:52 PMCanoeman says:
Good point.
Its true that the RF ferrite toroids for low frequency rfi filters (hf) frequencies are low permiability, but the toroids used in the Microwave bands (a very large part of the hobbie now) and the toroids used in switching power supplies, are high permiability, even some using neobendium toroids as chokes.
Many ham radio operators often build their own radios and amps, and power supplies etc. Those working in the microwave frequencies, usually build the bulk of their radios, due to the high cost of commercial microwave radios.
Toroids lose there inductance as the frequency increases, so rare metal ( neo) toroids work much better in high frequencies
Another good source are toroids used in defunct neon sign circuits.
That was an excellent idea, to use the CFL toroids, as reusing those tiny toroids keeps one more thing from the landfills.
On a side note, Ive switched from cfls completly, to LED lighting, saving the toxic chemicals and horrendous fluctuations of life time, in CFL's, caused by cycling the on off schedule of CFLs. CFL bulbs should only be used in lights that only get turned off and on once a day. normal multiple on off daily cyclces of CFLs, cause failure in CFLs in about a year. I think LED lighting actually makes CFLs defunct.
A great idea for an instructable how to video, might be the rescue of toroids from dead CFLs.
Thanks for the great info. :-))

Canoeman
Feb 1, 2012. 12:11 AMacmefixer says:
I don´t know how to say this without offending you, but I will because I don´t want others to read what you said and get the idea that it´s true. I´ve never heard of neobendium. I have heard of neodymium, but it is used in powerful magnets. Ferrite toroids are not capable of permanently retaining magnetism like a magnet, and do not use the rare metals found in magnets.

The stuff about hams is unrelated to this discussion, and doesn´t make sense to me. As for the lifetime of CFLs shortened by on/off cycles, I think you should worry more about keeping the electronics from getting hot and failing because of the heat. When the lamp´s base is above the CFL tube, the heat rises and makes the electronics get hot, so failure is more common.

LED lighting will eventually replace CFLs, but at this time very few people will spend twenty to forty dollars (US) for a single LED lamp when they can buy a CFL for 1/5th of that. And those are the prices we find in the Big Box discount stores! But given the time, the LED lamp will pay for itself in electricity savings. Another issue that seems to still plague LED lamps is that people think that they are all ¨too bright¨ or the light is too much like daylight. Nowadays the warm white LED lamps are available, too.

If you want to learn more about CFLs, go to http://donklipstein.com/ and read about CFLs, LEDs and fluorescent lighting.

About the only thing I agree is keeping the stuff out of the landfills. As for a video on salvaging toroid cores from dead CFLs, I think I´ve already seen something about that on Youtube.
Jan 2, 2012. 7:51 AMzappymax says:
eventually when you discard old lamps or circuitry, keep some of the toroids...
Feb 1, 2012. 12:23 AMacmefixer says:
Radio Shack sells toroids, but they are too expensive and are the kind of toroids found in motherboards, which are low permeability and need too many turns of wire. For some reasonably priced toroids, try mouser.com and search for Fair-Rite 2673002402 cores. They´re about 12 cents apiece. Another place is surplussales.com where you can buy the FT87-75 toroids which are big, but easy to wind and work with. You can get ten of them for $8.50 and a few dollars shipping.  BTW, they ran out of the green ones (I think I bought the last ones they had).
Jan 8, 2012. 7:02 PMluig says:
hello i have been trying to make one but i didoes work. yes i assembled just like it says in the diagram, but is there something else that could keep this from working? for example what would happen if i put many more coils on the Toroid. what if the emitter and the collector are backwards etc.
Jan 30, 2012. 5:05 AMacmefixer says:
It´s a blocking oscillator.  You can read more about it here.

The observer must view what happens in the Joule Thief in the time domain, not in the frequency domain.

I suggest you back up your claims with a link to an authoritative source.  That way, if the reader doesn´t understand your verbiage and double-talk (most likely), he/she can read more about it elsewhere.
Jan 31, 2012. 10:52 AMGary Viveiros says:
Acmefixer is right on the money! I was wrong in identifying the oscillator as a resonant colpitts. It is in fact a blocking oscillator with a square wave output. The biasing isn't right to allow it to oscillate resonant, because the frequency would have been up in the tens or hundreds of Megaherts. This oscillator is going at some frequency under a couple of thousand Hertz. Sorry, that I got you so riled up - my intention was not to mislead.  I thank you that you weren't so mad that you ignored my desire to be set straight.  It's no shame to be wrong once in awhile.  The trajedy is to stay that way and go through life with blinders on.  Thanks again .
Jan 9, 2012. 12:32 PMluig says:
ohh i just found found out that the led works at 4.5 volts could that affect this project?
Jan 28, 2012. 4:21 AMashy3321 says:
hey can any body explain the use of 1k resistor in this circuit and what if i cut it off
Jan 30, 2012. 5:00 AMacmefixer says:
It´s a blocking oscillator.  You can read more about it here.

The observer must view what happens in the Joule Thief in the time domain, not in the frequency domain.

I suggest you back up your claims with a link to an authoritative source.  That way, if the reader doesn´t understand your verbiage and double-talk (most likely), he/she can read more about it elsewhere.
Dec 26, 2011. 2:41 AMkostya says:
I've built a dozen of flashlights around this schematic using BC547 as an NPN transistor. They work well but efficiency is low. If electronic parts are so cheap in the Phillippines you may try to buy Zetex LED drivers. They are a bit tricky to solder being smd-components but adding a ready-made inductor and a resistor you will have a highly-effective flashlight.
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Author:ASCAS(ASCAS.com)
My name is "Angelo S. Casimiro", I am now 13 years old. I got interested in electronics and mechanics when i was 4 year old. And started soldering circuits (kits) at 7 years old. And improved solder...
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