How a Joule Thief Works

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How a Joule Thief Works
In this video we take alook at the Joule Thief circuit, examine how it works, and wind a bifiliar toroid transformer.
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FAQ:
Me: Paul, 49 from USA
Education: United States Navy, University of California at San Diego B.S. E.E., University of Pittsburgh M.S. E.E.
Experience: United States Navy STS, Bayer Intnl Process Engineer
Current: Teaching college freshmen electrical engineering at a small community college in the Pittsburgh Area.
Health: BAD (Congestive Heart Failure)
Hobbies: Electronics, flying, amateur radio, music (classic rock)

[@Telboy-fv8ke]

Great video as always, I used a Coil from a Poundland cheap doorbell. Impressed with the result. 72 Led's on low brightness under 400μA . Very bright if I turn download resistor. Uses max 12.42mA, on my YT. Keep up the good work

[@Enigma758]

"Solder flows where solder has been, so it's always best to tin tin tin" Love it! :)

[@teh60]

Reminds me of an ignition coil circuit on a car. Very thorough explanation, great video.

[@g00glian0]

I love hearing your positive upbeat voice when your videos start!

[@pauldery7875]

Thanks for the awesome explanation,

[@Skylineview713]

Great explanation of the Joule Thief. I've watched Clive's video a dozen time or more, I've also been watching what Julian Illet is doing with his circuits. I have found the bead sized inductors tend to run the battery down to around .2 or .3 volts. They are quite fun to wind too. I'm starting my own experiments with them, following Julian's lead.

[@learnelectronics]

It's all about having fun and learning.

[@timothyjohnson1511]

Please view the video of Steven Jones who has a much more interesting description of a similar circuit on Shameka Loeffler.

[@JuanPerez-uq5my]

Tanks to you, master... !!! I'm learning to fly in this electronic multiverse ... From Argentine, bye bye!!! 👋👋👋

[@stevehappe8583]

Good tutorial. Thanks.

[@dalenassar9152]

Special thanks for the added history and patent info...rare!

[@TheRadiogeek]

Fun stuff to play with. You did a nice job explaining it.

[@learnelectronics]

Thanks, I got a little tounge tired

[@marioarvizu7077]

You are simply AWESOME, to explain and teach. Thanks!!

[@mathmaker6946]

my circuit only worked with this video, thank you so much

[@thehappylittlefoxakabenji8154]

cool little circuit I made my first one in 1993 !

[@j.clowers7223]

Very cool to know.

[@albertcarpentercats]

I saw a joule thief that you can wind a air core type without a toroid and put the coils together to make a wireless unit to do what ever you make with a full wave rectifier and a electrolytic capacitor to it.and I tested it and it does work.

[@manukalias]

Nice 👍 Wish we could use similar Joule Thief in our life to boost it.😍🤩😍🤩

[@doctorbo5810]

Thanks a lot.

[@friedrichbendix7853]

Does this circuit work with any npn transistor? And can you scale it up to more volts and ampere?

[@davidb4081]

The little linear style through hole inductors will work just fine in place of winding your own torroid, if you wanted to make it look a little more streamlined. A pair soldered together make a peachy center tapped transformer. You can even omit the resistor, but to my calibrated eyeball it made no difference.

[@georgechambers3197]

Wow, all these new viewers and subs sure come with a lot more criticism! I seen joule thieves for years and just blown them off as pretty well useless, but your video kind of shines a new light on them. Thanks for taking the time and effort to make us a GOOD video!

[@learnelectronics]

Thanks buddy!! Good luck Monday.

[@axizepp]

its very important to mention that its very preferable to have a core with a flux reset path,like a ferrite with a non magnetic gap or powdered iron core. so when core will be energized,after that flux will fall to a much lower value (residual magnetization will be lower). that will make a greater efficiency of converter.

[@reeseyme9613]

i would suggest it will be much better to use a schematic diagram printout to explain the working then move on to breadboard to demonstrate.

[@anonymousacid9160]

just a cool addition to a joule thief: you can add a third winding on the transformer with a TON of turns to create VERY high voltages (unfortunately, with extremely low current). I got a 1.5v battery to go up to 50v that way. i think the 3-winding method is sued in many commercial mosquito zappers. just remember that people are not bugs, so dont zap them using this. i dont want to be the reason someone gets hurt lol

[@willhelmx8388]

Nice paul, how low can you get in voltage before the led goes out? forward voltage of the TR?, probably one have an overshoot when the field collapses.....this i must try with an old germanium... thanks for sharing, nice channel

[@learnelectronics]

Thank you. The toroid builds up charge as the transistor conducts. When the the it build up no more charge, the trsnsistor goes into cutoff. When this happens, the magnetic field in the toroid collapses and the accumulated charge is dumped at once into the LED, thousands of times a second.

[@EnergyTRE]

simplicity is divinity.

[@vincenttan1261]

Your Amazon link is not working.

[@alanbacknd3120]

Hi Paul, Great job on the Joule Thief. The web address for your store is wrong. The (S) is missing. Keep up the great work, Alan N8TIB

[@learnelectronics]

thank you. i fixed it.

[@alchemy1]

I don't understand why everyone mentions how to connect the two coil windings and yet they won't mention the reason for it. Better yet I don't see anyone asking why it is connected that or maybe have a mental picture for it. I simply see it as causing to current to flow in the same direction but oppositely wounded coil after I was able to cut through the cobweb of it in my mind. Anybody here that might know?

[@Ozzy3333333]

No disrespect here, but the explanation is about 5 of 10, why, does not show a schematic to make it easy to follow and he really does not explain it all correctly. Specially the boosting of the base voltage and EXACTLY why the transistor turns off. Most explanations I see are this way, incorrect.

[@jsflood]

Great video! 330'ish kHz square wave, could this be used as a clock pulse for a mcu 🤔. Not that it would be useful by any means tho. 😸

[@michaelpadovani9566]

You stole my joules and are losing your ground! Haha

[@learnelectronics]

Lol

[@DouglasKryder]

Paul, i could not get your store link to work, i think you left out the s on should be , i think all amazon stuff is https

[@learnelectronics]

You are correct.

[@Myreply59]

You have a perfect radio voice. If you haven't thought of being on a radio show, you should. Also, you explain the joule thief well, with a good model demonstration.

[@jerisin7202]

Steven Jones has a much more interesting description of a similar circuit on Shameka Loeffler.

[@WalterWhite-pr1qs]

What was the voltage increase? I didn't see any ☹️

[@bassblaster505]

3:00 2n2222 transformer got it

[@rodsofgod6863]

So its like a ram pump?

[@Migueldeservantes]

Well I may be wrong but in my personal opinion it is basically a pump... take very low wattage, and literally increase the "watts just above the threshold of the minimum voltage needed to have a power return on the LED... Please if I'm wrong just let me know! don't get angry at me, every one have their own way to make sense of how the world around them work!!

[@learnelectronics]

That's the basic idea.

[@genechanloui]

I was under the impression dc doesnt work inductors or transformers can anyone clarify

[@learnelectronics]

Transistors and inductors definitely work with DC. If they didnt we wouldnt have the tech we do today.

[@quantumlab9130]

I personally prefer a buck boost converter because they are much more efficient.

[@Ozzy3333333]

And it runs down to 0.2V? haha, I dont think so.

[@peterschets1380]

I saw in a other video that he was using a nail to act as a transformer. I am still not sure if it was a april fools joke. :)

[@WhoIsSam113H]

Just put a secondary winding on that toroid

[@TheKetsa]

Take care of your health.

[@learnelectronics]

Thanks, I'm trying to

[@RaymondReise]

nice videos, just a little tip, the mic doesn´t need to be that close, it´s kind of weird to hear the heavy breathing of anyone.

[@learnelectronics]

Why dont you read the video description before you make a fool of yourself with your comments. I suffer from congestive heart failure and use oxygen 24 hours a day. You would hear my bresthing if the microphone was across the room. If it bothers you, i invite you to watch a different video.

[@BushImports]

I usually use an air core coil or a pot core. Sometimes there is this really sweet spirit , I don know if it is God(Jesus) but where I usually get 19 or 20 volts I'll get like 42 volts. Thanks

[@feynmandirac7575]

Dude you just narrated Wikipedia article on this

[@michael-gary-scott]

oh my god your breathing is so loud

[@learnelectronics]

That's because I'm dying from congestive heart failure.

[@naturalmilkhoneyandzenretr9508]

@@learnelectronics I am an Rn ,n Natural healer and could help you. I need some electronic help so maybe we can work out something. I'm having a KZbin Awards Potluck Bonfire. APRIL 3RD. AT 2 LMK IF U CAN COME

[@Mr1bassman1]

Are you a smoker?

[@learnelectronics]

No, just dying from Congestive heart failure

[@oestrek]

TRANSISTOR! TRANSISTOR! not TRANSFORMER!

[@learnelectronics]

Slip of the tounge. My most humble apologies for offending you and causing you to YELL AT ME.

[@oestrek]

its not that I am offended. I know you are trying hard to do something here and I appreciate it. I really do but somewhere along the line someone needs to yell cut and run a retake of the scene even if the only someone is only a voice in your head. You do yourself a great disservice by making a LOT of speaking mistakes. It weakens your message which is essentially a good one. I know you need to get product out there and I can respect that but this video looks more like a last minute homework attempt. Nobody said it was going to be easy but if it its worth doing, its worth doing right.