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Author Topic: Joule Thief  (Read 6276450 times)

innovation_station

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Re: Jule Thief
« Reply #15 on: November 21, 2008, 07:12:11 AM »
i have used as low as 7 turns and lit 45 leds

the resisitor is nessary it is your freq... it chokes the first coil down and saturates the core  ;) ;D



ist

l8r 8)

Pirate88179

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Re: Jule Thief
« Reply #16 on: November 21, 2008, 07:51:04 AM »
@ IST:

Thank you.  These things are great are they not?  Such a neat little, simple device to help us totally drain our batteries.  Or, to use in other experiments...................

Bill

nievesoliveras

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Re: Jule Thief
« Reply #17 on: November 21, 2008, 01:59:15 PM »
Thanks to all

I made my first functionable Joule Thief.

Jesus

innovation_station

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Re: Jule Thief
« Reply #18 on: November 21, 2008, 03:51:48 PM »
here is my 7 trun tiny jouel theif powering 45 super bright leds in my grow lite design ....


there verry cool lil units ;)

i have built about 60 of thease units... ;D  in many diffrent configs....

i have made a unit that powers led flash lights...  :)  it is a module that takes the place of 2 batteries ...

it actually seams to lite the light almost as long from 1 battery as 3  8)

ist

@yucca  thank you ...   your scope shot confirms EVERTHING  ;)

i never bothered to scope it ..... lol

;)

great work.....   ;D 

Thaelin

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Re: Jule Thief
« Reply #19 on: November 21, 2008, 04:12:29 PM »
Hi bill:
   Here is a link to get the beginning of all of it. This is a set of on line lectures of many
different subjects. At the bottom of the list is a link to see all 3200+ videos. These are
made possible by the gov of india. Lots there to see.

  http://www.youtube.com/watch?v=w8Dq8blTmSA&feature=channel

thaelin

I found one on how the three phase motors work. In depth.


Pirate88179

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Re: Joule Thief
« Reply #20 on: November 22, 2008, 06:27:05 AM »
@ Thaelin:

Thanks for the link.  I will check them out...I have a lot to learn and I love learning.


Can anyone tell me how to tell the difference from the emitter and collector on the 2N3904 transistor?  I made my first joule thief and it does not work for some reason...yes, I'm sure it is something I did, or didn't do correctly.  I think I may have a polarity problem as the instructions indicate the collector and emitter but do not say which is which.  I am not talking about the middle lead, that is cool.  It is the ones on either end I am not sure about.  Thanks.

Also, here are some links to the Dr. Walter Lewin, MIT lecture series.  These are great, check them out.

http://www.learnerstv.com/course.php?cat=Physics

http://ocw.mit.edu/OcwWeb/Physics/8-01Physics-IFall1999/VideoLectures/

http://freescienceonline.blogspot.com/2006_07_01_archive.html


Bill

nievesoliveras

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Re: Jule Thief
« Reply #21 on: November 22, 2008, 06:33:45 AM »
@pirate

The correct definition could be this one:

Jesus

Pirate88179

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Re: Jule Thief
« Reply #22 on: November 22, 2008, 06:44:12 AM »
Jesus:

Thank you!!  The info for the 2N is right there, exactly what I needed.  I really appreciate your response.

Bill

capthook

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Re: Joule Thief
« Reply #23 on: November 22, 2008, 08:10:14 AM »
Also, here are some links to the Dr. Walter Lewin, MIT lecture series.  These are great, check them out.

http://www.learnerstv.com/course.php?cat=Physics

http://ocw.mit.edu/OcwWeb/Physics/8-01Physics-IFall1999/VideoLectures/

http://freescienceonline.blogspot.com/2006_07_01_archive.html

Bill

Thanks for the links!  I had seen a few videos of his lectures - and now there's vids of the entire course to absorb.

He is the mad professor type that teaches with enthusiasm that makes the learning even more interesting.

It's resources like these that make me still ohh-and-aah with wonder at the marvel of the internet.

 :)

Cap-Z-ro

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Re: Jule Thief
« Reply #24 on: November 22, 2008, 09:52:20 PM »

I thanked you for those links in a PM Bill.

Don't know if it got through tho, due to a browser glitch.

Thanks also to and Thaelin and jesus for the instructional info.

Regards...


Pirate88179

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Re: Jule Thief
« Reply #25 on: November 23, 2008, 02:24:51 AM »
@ Cap:

Yes, I received your thanks via pm.  No thanks needed.  I got the first link from someone on here about 6 months ago.  From there, I found the others.  I was so happy to get this information then, and I am glad to pass it on now.  I believe that is what this site is all about.....or should be. We all should exchange knowledge when we can.

Bill

Yucca

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Re: Jule Thief
« Reply #26 on: November 23, 2008, 03:31:24 AM »
Just some thoughts on this:

The thinnest wire I have is 30awg, I think if you use thinner wire then the average current consumption will go down and the LED will stay just as bright. If you want to use thicker wire then you can use more LEDs in parallel without upping current draw. The drive coil takes the current, the coil gauge needs balancing to the LED draw. If it´s too thick gauge then you use power and the LED won´t get any brighter.

I will try and unwind a cheap minispeaker coil out of a broken kids toy that I´ve seen kicking around the living room. I think maybe you could go REAL thin and up the number of turns a little on the drive side of the coil to make it much more efficient.

I have also had the thought of using the transistor case for the coil form using very thin wire with a superglue spot to start and finish the coil and decreasing the number of turns on the trigger coil to do away with the base resistor completely. Then it would just be 1 tranny, 1 LED and some really thin wire. Maybe the ultimate minimalist joule thief  :)

Yucca.

Pirate88179

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Re: Jule Thief
« Reply #27 on: November 23, 2008, 03:59:21 AM »
@ Yucca:

Sounds good.  Go for it and let us know what happens.

Bill

WilbyInebriated

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Re: Jule Thief
« Reply #28 on: November 23, 2008, 08:02:32 AM »
Just some thoughts on this:

The thinnest wire I have is 30awg, I think if you use thinner wire then the average current consumption will go down and the LED will stay just as bright. If you want to use thicker wire then you can use more LEDs in parallel without upping current draw. The drive coil takes the current, the coil gauge needs balancing to the LED draw. If it´s too thick gauge then you use power and the LED won´t get any brighter.

I will try and unwind a cheap minispeaker coil out of a broken kids toy that I´ve seen kicking around the living room. I think maybe you could go REAL thin and up the number of turns a little on the drive side of the coil to make it much more efficient.

I have also had the thought of using the transistor case for the coil form using very thin wire with a superglue spot to start and finish the coil and decreasing the number of turns on the trigger coil to do away with the base resistor completely. Then it would just be 1 tranny, 1 LED and some really thin wire. Maybe the ultimate minimalist joule thief  :)

Yucca.

heres some data on different cores and turns
http://www.prc68.com/I/LED.shtml#BO

spinner

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Re: Jule Thief
« Reply #29 on: November 23, 2008, 09:40:55 AM »
Hmm, this circuit (a very basic transistor oscillator with an inductive coupling) is called "The Joule Thief"? Lol,  I can assure you it's more like a "Joule waster"...

Yes, it works with only a few (easy to get or make) components, but that's about all it can do...
It actually works as a (quite inefficient) DC to AC/frequency converter, wasting at least half of the Energy available.

Maybe it's the rather low input voltage where LED is still working that fascinates you?

There are serial (three/four pin "transistor like") components on the market, which allows you >85% efficiency (DC/DC chips, usually needing only a few external low-tech components to work). They all beat this circuit (in efficiency) at least by the factor of two... And they're still not Unity.

Joule Thief? Yeah, sure...