All You Ever Wanted To Know About The Joule Thief

All You Ever Wanted To Know About The Joule Thief - but where afraid to ask your Mother lol

[@shanejohns7901]

"A “Joule Thief” is a simple voltage booster circuit. It can increase the voltage of a power source by changing the constant low voltage signal into a series of rapid pulses at a higher voltage."

[@pk2712]

In your first diagram with the led in parallel with the inductor , you need to reverse the polarity of the led in order for the led to light .

[@solarhope]

I just realised its been 44 years since formally studying this at tech college as a telecoms apprentice. You show it is still understandable without the maths! - great start.

[@AshleyMillsTube]

solarhope cheers mate, my belief is that the maths is slave to imagination, a useful symbolic reduction for when we need something concrete to hold onto, but i think most of it can be visualised and understood without ever formally symbolising it

[@Buzzhumma]

great explanation Ashton, and nice to meet you. I was always under the impression that the winding being in the opposite direction on the primary would be blocked by the secondary as an opposing field being that as the primary field builds and so to does the reverse blocking secondary field but your explanation gets me wondering . thanks for you effort😀

[@1495978707]

4:10 Your diode is backwards in this diagram. When the switch closes, the inductor uses its stored magnetic energy to continue driving some current in the same direction.

[@ronvanwegen]

Best explanation of Joule Theft on the internets I've seen (and I've seen quite a few). Full marks. Excellent video.

[@knoxpruett1889]

And that, is the way to explain the operation. Section by section, then put them together! Great job Robert!

[@ThinkingandTinkering]

cheers mate

[@BillHester2011]

Cant believe this was made... nearly 7 years ago! What a great explanation.... feeds curiosity!

[@NiVofHiR]

I think your on it mate! Keep up the good work, this would be a good video to redo, only make it shorter, more concise. One of the best joule thief explanations I have seen to date after almost a decade of joule thief learning and experiments. Big up to the Robert Murray of the Smith as well! BRAVO LADS!

[@shermluge]

I've seen several explanations, I understood the basics, but this really made it crystal clear..Thank you..

[@aravindhvasu195]

That was purely awesome!!! Excellent mate ...thank you

[@gfridhar]

That was fantastic. The detailed description of the concept is really good. Many a thanks for this video.

[@ArtisticImpressionsbyBobRouth]

Thank you so very much....I NOW understand. It sure is alot easier to wind a nail or spike instead of winding the torrid ring. This was the most useful video I've watched in a long time.

[@AshleyMillsTube]

***** cheers mate!

[@joeyocom5087]

Ferrite works better, that is why it is used

[@igwechi]

Brilliant video, I like how you started out with the conceptual foundations.

[@johnrussell5598]

Great Explaination. Inductors are fascinating. Thanks J.R.

[@Spinningininfinity]

Ahh, the good old TNT revisited Still so useful, still so worthwhile.

[@debeshbhattarai]

You really inspired me so much... very easy explanation of Joule thief circuit... Cheers..!

[@deathkeys1]

have I already told that I love this channel and you guys are awesome? if not, consider that!

[@ThinkingandTinkering]

+William A. lol - will do mate and cheers

[@BobMellor1954]

Thank you Ashley, you have provided a clear understanding of how a back emf works that I can fully understand; keep up the good work. Regards Bob

[@gorgephillips1565]

I have been watching you last week takeing kn everything your teaching me i love it want as much you asyou can put outaneedto know please more of old batteis know one had time to tel, me thank you ever much your new student G.R.P.

[@billbailey4615]

i finally understand this circuit.i have sadly watched way to many video's,but this explained it in simple terms.it can be replicated easily.RMS is a master at this game,if he hangs with Steve i would imagine he is very competent also.I'm glad you were allowed to join with them . i expect great things from you as this is one of my most trusted sites.no bs or tricks there ever.thank you

[@jprice1122]

Nice addition to the team... :)

[@AshleyMillsTube]

J Price :)

[@ThinkingandTinkering]

J Price he is a clever boy lol

[@jeromekerngarcia]

*+Robert Murray-Smith:* Where-ever did you find a soft-iron nail to use for xfrmr core? Almost *all* nails are made of mild steel = poor choice for xfrmr cores!

[@8ank3r]

Thanks so much for the simplification, i think my little mind can comprehend it now :)

[@DwiNoviantoUntidar]

Can u tell me the formulas to determain how many turn should i do to make those coils? thanks at first.

[@synespro]

Awesome thank you. ive never found a good joule thief explanation so black and white. Again thanks for making this and i look forward to more teachings in the future. A practical use for a joule thief is an earth battery light and/ or a crystal cell battery

[@AshleyMillsTube]

***** cheers mate, earth battery sounds rad

[@TheJaCaMo1]

Ah brilliant video! I was waiting for this to come - and then be linked to capacitor discharging :) good stuff!

[@AshleyMillsTube]

Jacques Reynaud cheers!

[@francismannion7075]

Great video!!!! It was fun watching and I learned a lot.

[@just1fix2004]

Great Joule Thief tut man, I think it will be handy for the power I'm trying to harvest.

[@AshleyMillsTube]

***** cool

[@jamiejoker118]

I call it the see seesaw effect nice down to earth illustration thanks.. NOW we want a video using the idea with a super cap setup via solor panel

[@brucewayne-cave]

Outstanding Job !!!

[@BrentLeVasseur]

Who is this bearded, meditating, mushroom loving, hippie genius? 😂😂 Seriously though, brilliant explanation! And it’s the perfect case study in non-linear dynamics. IE…how do you create a circuit that automates and regulates itself through non-linear phase and field transitions? That’s no joke, genius stuff right there!

[@danajohnson3799]

It's always difficult to know who your audience is on You Tube and their level of understanding. All in all, a very good operational description of the "Joule Thief" circuit. The only comment I would make is to avoid the use of acronyms such as EMF (Electromotive Force) without explaining what EMF is. If you use electromotive force in your presentation then counter electromotive force should also be explained and used, otherwise just use voltage. It's a small criticism, which indicates how good your presentation was. Thanks Ashley!

[@AshleyMillsTube]

Dana Johnson thanks Dana, good point about the acronyms, so easy just to assume people know or even overlook it entirely

[@DrSaminstine]

Great insight into the circuit and nicely explained I always enjoy this channel and this was no exception thank you for sharing

[@AshleyMillsTube]

DrSaminstine thanks man :)

[@LostInLeiden]

@ashley mills, excuse my ignorance but at 4:05 you say the direction of the coil winding is important to determine which way the magnetic field (and therefore the EMF) builds up when switched on (and then off) but doesn't an inductor always build up an EMF that opposes the current creating it, so does the winding direction really play a role or am I missing something?

[@tlar1272]

Is the LED at 3:30 facing the wrong direction? Like a fly back diode. But with light. Thanks for the detailed explanation!!

[@FireSymphoney]

wonderful wonderful explanation, the best explanation I found online.

[@chifoltz9023]

Awesome, thank you! Just out of curiosity, did you just finish installing a transmission before you made this video?

[@kingshahzad78]

The best Explanation ever. Thanks❤❤❤❤

[@emcgon]

Nice explanation - thanks. However, in the first diagram (beginning at 3:24) I think you are showing the LED the wrong way around. The back-EMF induced across the coil when you open the switch will be more positive at the switch side than at the 1.5V rail side, so you will need to connect the LED the other way around for it to light.

[@randomlettersqzkebkw]

Please please... keep all your explanations as simple as this. Very good explanation!

[@AshleyMillsTube]

randomlettersqzkebkw thanks man

[@jeffpatrick1864]

Great work bub! Inadvertently answered about a hundred other things I needed answered. Thanx Wow, such an old vid lmao

[@GreenmeResearch]

Great and clear explanation. Talking about Back-emf are you known with the delayed Lenz law?

[@AshleyMillsTube]

Greenme Research cheers mate, i've not looked at the delayed lenz law mate

[@crusaderanimation6967]

5:14 "Transformer works by warping another coil on the same nail" I love and hate this quote so much XD

[@rctbone100]

what determines the on-off frequency, and by changing the transformer what range of frequencies can you create? Any shielding suggestions for use in an airplane??

[@omsingharjit]

so we can say it can increase or bost voltage ?

[@br.davidriccio5898]

Thanks a million for this simple video! I've been trying to get this Joule Thief to work but to no avail. Now I stand a chance to get it to work. BD

[@ThinkingandTinkering]

cheers mate

[@evanleebodies]

Brilliant explanation

[@triumphmanful]

So what can I make at home with this info. ? Anything I can use for security lighting, plant growing, or ? would be useful . Thanks

[@billspradlin9619]

Isn't the Diode drawn in the wrong direction? Because when the switch is closed the current will go through the diode not the coil. This is similar to a diode on a relay coil and normally the cathode of the diode is towards the positive rail. This type of arrangement is usually called the flyback diode. I could be wrong.

[@ThinkingandTinkering]

+Bill Spradlin so could i mate - but i don't think so - i will recheck though

[@luisrolon6421]

maxwell wrote about this. he noticed that the pulse after system was turned off had MORE ENERGY than original pulse!!!!!!!. to me that is the key to overunity. the key to overcoming back emf etc.

[@kingshahzad78]

The Best Explanation Ever

[@fredriko.zachrisson9711]

Hi Robert. I recently discovered your graphene videos, and i read that you have written a 101-book that seemed like a great book from what ppl had to say. I just wanted to ask where i can order a copy? Thanks in advance. /Fredrik.

[@ThinkingandTinkering]

+Fredrik Zachrisson It's on smashwords mate and i believe amazon

[@InterdimensionalWiz]

superb description! like this guy...can you do the same with voltage multiplier and the fractle volt divider.... ta!

[@andrewkhchan]

How many turns of winding on the nail ? Thx

[@alphonseprecis2302]

13:30 did you just crawl from under a car you're repairing next door? Even academics can afford a comb, a bit of soap, a clean T-shirt and a less scruffy sweater

[@cphank3722]

The LED at about 3:30 to 4:15 is connected backward in the whiteboard schematic.

[@Ozzy3333333]

He has most of it right, but not all of it. Specifically the turn of mechanism of the transistor. 11:20

[@digitalfun59]

Great presentation.

[@AshleyMillsTube]

Artist Group cheers dude!

[@TheGEODEAHOLIC]

good addition to the team, nice 1st effort at explaining & demonstrating the joule thief.

[@AshleyMillsTube]

TheGEODEAHOLIC cheers, took me enough time !

[@TheGEODEAHOLIC]

these things are a learning process, rob has done hundreds, you'll get clearer & more efficient with practice over time. good 1st effort.

[@AshleyMillsTube]

TheGEODEAHOLIC thanks for the encouragement!

[@martinnottsperfectcoins1930]

wow i actually understood every thing you said 10 out of 10 great teacher very fun to watch you guys

[@ThinkingandTinkering]

+Margaret Wallbank lol - thanks very much

[@jorgenieto2972]

Awesome info thanks

[@AshleyMillsTube]

Jorge Nieto cheers

[@amirrahiminia2556]

Very interesting and thank you for sharing it with us but I think the problem with this circuit for stepping up the voltage is efficiency which seems to be bellow %50. I wounder if a resistance load to collect the short cut phase of the oscillation would effect the circuit. ie. between Emitter and Ground.

[@muhammadarifwicaksono476]

Excuse me, i want to ask, what the other name of joule thief in electronics theory exactly? thank you.

[@PoiSonSonic]

Hello Ashley. I'd love to see more of your videos. Please tell me where to find more. Cheers

[@corywilliamsmith]

Yes I really like your teaching

[@BluesDoctor]

Ashley, if you want to take this to a next practical step, review a voltage multiplier. Image Intensifier is high voltage tube that runs on AA battery. Cold plasma another application with some very cool applications where this can be used. No end to what can be done with cold plasma device. My experiments investigating healing graphene defects with CP, if you want practical application. Cheers mate, you are doing good work.

[@AshleyMillsTube]

BluesDoctor thanks for the tips, I'm excited to see where this stuff goes. Good luck with the graphene defects stuff, sounds interesting :D

[@BrentLeVasseur]

Wow! So you have actually healed graphene using cold plasma? That’s like a Nobel Prize level accomplishment. Why haven’t you demonstrated this or published any papers? By the way, if it does work as you claim then what you have demonstrated is known as ‘negative entropy’ which is the second law of thermodynamics working in reverse! That’s bigger than Relativity in terms of its impact on physics.

[@shaunlastname391]

Could've spent the 16 minutes walking to a shop and buying this magic for a pound in a cheap torch ffs. An led driver wow This guy needs to have a word with his mushroom pals, they're taking the piss out of him

[@skrame01]

Great job great explanation.

[@ThinkingandTinkering]

+Stephen Kramer cheers mate

[@sparkfishes]

Love the channel. I a bit puzzled when the relay and the 555 timer is introduced as surely that needs 12v and 9v respectivly to work .that is not referred to and seems to move away from the original intention of boosting a 1.5v battery to drive a LED

[@newmonengineering]

You can ommit the 555 timer in the relay circuit. Feed the relay coil through the normally closed contact. By doing that, the relay will turn on in the off state, and off as soon as the contact breaks. It's commonly called a relay buzzer circuit. If it is controlling different voltages you need a dpdt but if it's the same you can use a dpst. It has to be a double pole with a nc and no connection. Normally Closed and Normally Open.

[@robertlanham8076]

Great video young man, robert I could see your mannerism's in that young pandawan

[@AshleyMillsTube]

robert lanham haha, just need to get myself a boiler suit and a ciggie lol :D

[@planetlimbo5981]

Would a bifilar pancake coil help pull the current more?

[@joshuaamerson2365]

The windings a 1:1 or the secondary need more windings?

[@gristlevonraben]

it was extremely educational, thank you very much.

[@AshleyMillsTube]

Gristle Von Raben cheers man :D

[@bushidobadboy]

"After I had meditated outside for a coupe of weeks..." Ha, classic, love it. And I liked the way RM-S looked round, at the amusing comment.Love the films gentlemen. As a bit of a youtube educator myself, I applaud what you do!Question: is there any way that old batteries could be utilised, via the joule thief (or other method), to help charge a 1 mega farad capacitor? That would be a nice way to use other peoples waste batteries to help power a home or car? Just an idea, sorry if it is patently ridiculous - my primary area of knowledge is the Human body/brain, and I got a piss-poor grade in my A-level electronics exam, lol.

[@ThinkingandTinkering]

+bushidobadboy lol - cheers mate and i will have a look into that - good idea!

[@THOMASTHESAILOR]

Excellent Video Mr. Smith, How about a video on the current flow involved in a Joule Thief. You'll definitely need an oscilloscope to really look at that circuit. It's truly amazing

[@ThinkingandTinkering]

+ThomasTheSailor Chubby i'll have a look at it mate

[@yethinderragav]

Awsm vid!

[@joeyocom5087]

I have wired a Ferrite ring in parallel with telephone wire.... (2 sets of windings, counter rotating) ........and it will light the LED down to .31 V, with a TIP31 Transistor.....470 resistor ......................... at .31 V it stops working. Best coil I have made so far. Ferrite Tubes are noise suppressors in certain electronic cables, computers monitors etc THEY WORK GREAT !!! and are compact !!

[@mukundsrinivas8426]

excellent vid. Looking forward of more of these. The mushrooms remind me of frank gallagher

[@AshleyMillsTube]

mukund srinivas cheers mate, not sure about the frank gallagher thing hehe

[@mukundsrinivas8426]

Haha. Frank loves mushrooms ain't it. But yea man, great video

[@ArtisticImpressionsbyBobRouth]

Can you increase the output by increasing the input or could you run multiple joule thieves' in a series?

[@AshleyMillsTube]

***** increasing the input will increase the output, but the point here is to run it down to a low voltage, it would be interesting to try connecting a bunch of these up in parallel. I would like to understand the load characteristics

[@metitusable]

What about using just a transformer to escalate the voltage? Thanks

[@icebluscorpion]

You can go further and ditch the 555 timer get a relay the two separated contacts to build two separated circuits. The one switch (NO) is attached with the julethief. And the second relay switch (NC) is in series with the relay coil and the relay will buzz happily away like a buzzer. Note both switches have to be electrically separated they are two different circuits the are only mechanically connected in the relay.

[@Chadwickyboy]

I believe your LED is backwards in your whiteboard diagram around 4 minutes in... no? Looking at the coil: upon opening the switch, the lower portion of the coil will at positive potential, reverse biasing the diode.

[@thebeststooge]

I just stumbled onto you and this video and I must say very well said. Video editing sucked but your explanation was spot on. Now I have read that the type of inductor used helps with efficiency so you can go even lower so a nail will work, or any metal, but is not optimal as say a toroid. I know that it matters EXTREMELY which transistors you use and a germanium transistor has a lower starting voltage so that .7v to kick it on suddenly becomes .3 or .4 so even more of the battery, or an even lower voltage solar cell, can be used.

[@ThinkingandTinkering]

+legalizeshemp420 cheers mate - thanks for the input

[@roman_abelardo]

Gracias por su aporte, una pregunta: es factible emplearlo en un circuito de Radio Galena sin energizar? con el fin de aprovechar las señales de radio frecuencia 🤔

[@planetengineeringofficial8545]

nicely done! :)

[@AshleyMillsTube]

сталкер чворович cheers man

[@CountryHouseIncubators]

Thanks for the video. I noticed you said the voltage out depends on the rate at which it switches on and off. If I use your setup in simualtion you get Huge voltages over 100V and everything explodes and yet yours doesn't. Is there a reason why this isn't a reality?

[@NorthernKitty]

I realize this is 3 years after you asked, but as I understand it the voltage will be limited by what the LED draws. I know they warn against letting this go "open circuit" as the voltage will spike very high across the transistor. (And I think this is why it's important that he mentions the battery MUST supply less than the LED needs, so that the transistor shuts off and recycles everything.) If so, I would think it wise to design "over-voltage protection" into the circuit. Perhaps the simulations don't account for an upper limit on the LED? But in reality, I think the LED just happily draws what it needs and stops there. Someone please feel free to correct me if I'm wrong, otherwise I hope this is helpful.

[@PulseFuelNerd]

How does joule thief- joules per lumen compare to standard LED joules per lumen?

[@weareelectricgi]

very well explained

[@ThinkingandTinkering]

cheers mate

[@joeyocom5087]

A nail will work , but Ferrite works better

[@iluzyon1]

I realise iwas missing some point about the dinamic of the joule thief... Thanks for sharing these infos. And thanks to Robert for leting you in ;)

[@AshleyMillsTube]

iluzyon1 hehe, cheers man, glad you found it useful ;)

[@ThinkingandTinkering]

iluzyon1 Ash is a star mate - it's good to have him around - you should be in the lab - some of the ideas we come up with while chatting to each other is just amazing

[@TheJaCaMo1]

Robert Murray-Smith I think this may be the start of something beautiful...

[@ThinkingandTinkering]

Jacques Reynaud absolutely lol

[@Equinoxtrills]

I've built dozens of joule thief...and this is a good explanation, why dozens? Good for laser driver (sometimes...depends on the laser diode)

[@AshleyMillsTube]

Aria C Bramanta cool, cheers mate

[@ArbitraryOnslaught]

More then decent explanation!

[@6969smurfy]

Nice info.

[@AshleyMillsTube]

Dan Murphy thanks

[@userou-ig1ze]

how can people do this with inductors only, no toroid? Some circuits achieve this using a capacitor and multiple inductors

[@alphonseprecis2302]

At 1:28, "The electromagnetic field induces a magnetic field in the iron". Hmm. Put my mom's iron in the microwave to see by experiment, lots of sparks and bangs indeed, lovely magnetic field effects! Unfortunately it left the iron afterwards, in the form of blue smoke and won't come back.

[@RodgerLucky714]

1.5v? that battery looks bigger than my house

[@Hhydrogen4Power]

I used this as a demo for some idiots and they got it, thanks.

[@AshleyMillsTube]

Hhydrogen4Power haha, cheers mate

[@Hhydrogen4Power]

Ashley Mills well you did a good job. The electric Magneto Effect en.m.wikipedia.org/wiki/Magnetoelectric_effect is what the basic idea of bouncing the energy is. "Mindful of Roberts rules," I thought you would find this interesting. It's surprising how well it works and how you can tune it. Cheers David A Puchta

[@AshleyMillsTube]

Thanks that looks interesting :)

[@Hhydrogen4Power]

Ashley Mills your welcome, FYI it's 10:02 Am in San Diego California and you responded at 9:30ish. I truly an enjoying Roberts channel and your addition is way cool. Sometimes a chemical energy-related relationship between friends can get amazing things done.

[@AshleyMillsTube]

it's cool to be able to meet people from all around the world on here! I'm enjoying being part of the channel. Got some interesting things planned :)

[@audio211]

Bro thanks for the very nice explanation about the concept of circuit now I got an idea to develop it much later. Can I aplly this circuit on inverter?plss answer ty

[@audio211]

Apply sorry

[@pauls7755]

I dont know much about electronics - but this was clear and REALLY interesting. When you say that you can power a 3V device usiing just 1.5V of energy I Initially I thought "OMG free energy!" But then thought of the First Law of Thermodynamics - cant create something out of nothing. But what you are really doing is just making it more efficient ? Just wondering how this effects the overall life of the battery ? Anyway, REALLY well explained - I hope you go on to make other videos. Cheers!

[@ThinkingandTinkering]

there's no free energy here mate - you are right it is just an efficiency and depth of discharge thing - i have no idea on cycle life as i have never tested it - but that would be worth doing