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Author Topic: Acme Fixer's highly efficient Joule Thief help needed.  (Read 36005 times)

Legalizeshemp420

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Acme Fixer's highly efficient Joule Thief help needed.
« on: October 11, 2013, 04:20:33 AM »
https://www.youtube.com/watch?v=uSVLemZFAbs

The LED is a 3.2V @20ma 16000 mcd variety and the video shows some results I need help with.  The biggest thing I need help with is how to accurately measure efficiency with a scope and a DMM because that is all I have.

Legalizeshemp420

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #1 on: October 11, 2013, 02:46:23 PM »
Here is the schematic diagram as I can't find the link on his very discombobulated blog.

The one I replicated is the top one and no matter what I changed the frequency would not budge.

gyulasun

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #2 on: October 11, 2013, 11:21:24 PM »
Hello,

The new blogsite is http://rustybolt.info/wordpress/?page_id=560   

I tried to search for the circuit you refer to above but has not found.  I found this though:

http://rustybolt.info/wordpress/?p=221

By the way he is also a member here if I recall correctly: http://www.overunity.com/13175/25mv-joule-thief-powered-by-peltier-merely-using-our-body-heat-free-energy-247/msg351059/#msg351059

Gyula

TinselKoala

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #3 on: October 11, 2013, 11:30:29 PM »
Here is the schematic diagram as I can't find the link on his very discombobulated blog.

The one I replicated is the top one and no matter what I changed the frequency would not budge.

What do you mean? There are many things that should change the frequency of any JT circuit. Change just about anything and the frequency will change.  The frequency will change even as the supply battery voltage drops, as the transistor warms and cools, as you change winding numbers or even the position of the transformer wrt the other components.

Are you sure, with your new scope, that you are actually displaying the frequency of the JT's oscillations and not something else? I remember we had some trouble with that when you were using the simulator. Several times you had displays that didn't actually show what the JT was doing but were missing the JT oscs or were showing probe and instrument noise only.

ETA: How many turns on the little toroid? (I had to take apart 3 CFLs to find a 3/8" toroid.)

Legalizeshemp420

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #4 on: October 11, 2013, 11:48:17 PM »
All I know is that it is hooked up on the anode and cathode of the LED and that 400khz is what I am getting to it.

For those who may have missed the image.


TinselKoala

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #5 on: October 12, 2013, 12:07:27 AM »
All I know is that it is hooked up on the anode and cathode of the LED and that 400khz is what I am getting to it.

For those who may have missed the image.

Did you wind the toroid?

Well, that certainly looks like a JT waveform. What's the timebase setting? What happens when you bring a strong magnet over to the toroid?

Legalizeshemp420

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #6 on: October 12, 2013, 12:20:02 AM »
Frequency changes.

The toroid I did not wind but performs exceptionally well in my standard JT so I am using it for this purpose but 400khz?

Timebase setting is .5us (lowest this 20mhz scope will go) and I counted about .5 for a full wave which is .25us for the period.

TinselKoala

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #7 on: October 12, 2013, 12:20:44 AM »
Silly me, I put two layers of #27 on my little 3/8 inch toroid from a CFL before I measured it. It was 1.5 milliHenry! Now I've stripped off all but 14 turns (each winding) and it still measures 500 microHenry.

How many turns on the toroid?



Legalizeshemp420

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #8 on: October 12, 2013, 12:23:25 AM »
18 on each side of 20 or 22ga wire or possibly 24ga but no smaller wire.

I can't measure the inductance value of it myself though.

TinselKoala

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #9 on: October 12, 2013, 12:29:33 AM »
Frequency changes.

The toroid I did not wind but performs exceptionally well in my standard JT so I am using it for this purpose but 400khz?

Timebase setting is .5us (lowest this 20mhz scope will go) and I counted about .5 for a full wave which is .25us for the period.

There are 9 minor divisions across the shot you show. That makes 9 x 0.0000005 sec = 0.0000045 sec or 4.5 microseconds for the full screen. There are 17 full periods shown. 17/0.0000045 = 3.78 MegaHz. 

It's easy to misplace decimal points, for sure, I do it all the time, and maybe I did again. But whenever possible on an analog scope, use as many screen divisions and peaks as possible to do your frequency calculations. Accuracy improves with more cycles and more divisions.

Legalizeshemp420

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #10 on: October 12, 2013, 12:32:25 AM »
There are 9 minor divisions across the shot you show. That makes 9 x 0.0000005 sec = 0.0000045 sec or 4.5 microseconds for the full screen. There are 17 full periods shown. 17/0.0000045 = 3.78 MegaHz. 

It's easy to misplace decimal points, for sure, I do it all the time, and maybe I did again. But whenever possible on an analog scope, use as many screen divisions and peaks as possible to do your frequency calculations. Accuracy improves with more cycles and more divisions.
You lost me.

In that shot I was counting the middle reticule until I saw the same pattern with the next wave.  I counted that at 2,4,half way between, 6,8,div.  So, .5?

TinselKoala

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #11 on: October 12, 2013, 12:32:30 AM »
18 on each side of 20 or 22ga wire or possibly 24ga but no smaller wire.

I can't measure the inductance value of it myself though.

Sure you can. You have a scope, right? Set up a tank circuit with a known capacitance, poke it with a little jolt from a power supply and measure the ring frequency. Then calculate the inductance based on the capacitor value and the measured frequency. That's how inductance meters do it.


Legalizeshemp420

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #12 on: October 12, 2013, 12:35:42 AM »
I know what I meant was I don't have a way to constantly poke it since I can't freeze a capture like I could in a DSO.  Because I can't do that I would need something that repeats.  I saw the circuits but do not have the parts here to replicate.

TinselKoala

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #13 on: October 12, 2013, 12:35:57 AM »
You lost me.

In that shot I was counting the middle reticule until I saw the same pattern with the next wave.  I counted that at 2,4,half way between, 6,8,div.  So, .5?

Look at the screen graticule markers. There are nine full divisions across the scopeshot you showed. That means there are 9 x 0.5 microseconds across the whole screen. Right?

How many peaks are there across the whole screen? Since the first one is aligned with the first leftmost graticule line, it is the "zeroeth" one and doesn't count. SO there are 17 peaks across the screen until you get to the rightmost graticle marker shown. You have 17 full cycles in 4.5 microseconds.

Your own value, 1 cycle in 0.25 microseconds, also yields a value of 4 MHz, not 400 kHz.

Legalizeshemp420

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Re: Acme Fixer's highly efficient Joule Thief help needed.
« Reply #14 on: October 12, 2013, 12:38:45 AM »
Look at the screen graticule markers. There are nine full divisions across the scopeshot you showed. That means there are 9 x 0.5 microseconds across the whole screen. Right?

How many peaks are there across the whole screen? Since the first one is aligned with the first leftmost graticule line, it is the "zeroeth" one and doesn't count. SO there are 17 peaks across the screen until you get to the rightmost graticle marker shown. You have 17 full cycles in 4.5 microseconds.

Your own value, 1 cycle in 0.25 microseconds, also yields a value of 4 MHz, not 400 kHz.
Ahhhh, we came to the same result only via a different path PLUS that damn misplaced decimal point, lol.  btw, 4mhz makes more sense than seeing that many patterns on my 20mhz scope for a 400khz signal.

Now, UGH 4mhz?  WaTaH?!?  lol