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Author Topic: Is joule thief circuit gets overunity?  (Read 604076 times)

MileHigh

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Re: Is joule thief circuit gets overunity?
« Reply #675 on: April 29, 2013, 12:10:27 AM »
Poynt:

You have some awesome new equipment.  You know how computer-generated imagery in movies is now almost indistinguishable from the real thing... Well I assume that your DSO is from the latest generation and it looks awesome.  So if I had a choice today I would take a high-end DSO over a high-end analog scope.  Just pop your data onto a flash drive if you need more crunching.

If I was going to really scrutinize the data I would double-check how well the sharp spikes are being sampled. I assume that you could do that by simply stretching the time base out centered on the spikes and eventually the display will show you the true data and not the display-filtered data.

Have fun!

MileHigh

P.S.:  No more floppy drive?  lol
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poynt99

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Re: Is joule thief circuit gets overunity?
« Reply #676 on: April 29, 2013, 12:12:25 AM »
PW,

I'm not certain if Lawrence posted scope shots for this board #33. If he did, it would be several pages back I guess.
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poynt99

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Re: Is joule thief circuit gets overunity?
« Reply #677 on: April 29, 2013, 12:16:13 AM »
MH,

The spikes represent such a small magnitude and time component of the overall wave form that its value would have little affect on the results.

Yes, definitely nice having a USB drive. Too bad this scope isn't mine. But I still like mine, floppy drive and all. ;)
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picowatt

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Re: Is joule thief circuit gets overunity?
« Reply #678 on: April 29, 2013, 12:16:18 AM »
Quote from: poynt99 on April 29, 2013, 12:03:33 AM
The Output scope shots:

tek006 through tek008 illustrate how the Output Voltage and Current wave forms vary as the Input Voltage is varied from 0.53V to 1.35V.

Not taking into account the drops in the CSR resistors, a rough COP can be calculated by dividing the average Output Power by the average Input Power for a corresponding Input Voltage.

Input Voltage (0.515V, and 0.53V)
Pout = 3.68mW
Pin = 5.66mW
COP = 0.65

Input Voltage (1.35V)
Pout = 39.8mW
Pin = 48.4mW
COP = 0.82

Short video of the Input Voltage sweep to follow...

.99,

The COP's are consistent with best guesses.

So far, the only scope shots I have found from Lawrence that reference board 33 are in reply #240 and #241 on page 17.

The captures referenced for board 33 are particularly noisey with waveforms different from your captures.

PW

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picowatt

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Re: Is joule thief circuit gets overunity?
« Reply #679 on: April 29, 2013, 12:22:17 AM »
.99,

It is looking safer to say that Lawrence's scopes have offset issues.  Particularly his captures wherein the input current trace is clipping on the top edge.  That clipped level is looking like the true zero ref line.

Damn that's a nice scope...

What's the vertical resolution bitwise?

PW

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MileHigh

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Re: Is joule thief circuit gets overunity?
« Reply #680 on: April 29, 2013, 12:24:51 AM »
Poynt:

Indeed, I hadn't thought about the narrowest parts of the spikes not being too significant for the overall power calculation. 

I guess you can call yourself an "old timer" when you look at one of these new scopes, and to your surprise there is very little front-to-back depth to them.  I don't know if that's the case with your high-end model.  We are so used to scopes being heavy and and at least 14 or 15 inches in depth.

They feel "chopped off" to me!  What happened?  lol

MileHigh
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ltseung888

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Re: Is joule thief circuit gets overunity?
« Reply #681 on: April 29, 2013, 12:30:25 AM »
Quote from: poynt99 on April 29, 2013, 12:03:33 AM
The Output scope shots:

tek006 through tek008 illustrate how the Output Voltage and Current wave forms vary as the Input Voltage is varied from 0.53V to 1.35V.

Not taking into account the drops in the CSR resistors, a rough COP can be calculated by dividing the average Output Power by the average Input Power for a corresponding Input Voltage.

Input Voltage (0.515V, and 0.53V)
Pout = 3.68mW
Pin = 5.66mW
COP = 0.65

Input Voltage (1.35V)
Pout = 39.8mW
Pin = 48.4mW
COP = 0.82

Short video of the Input Voltage sweep to follow...
@poynt99,
 
Can you please take shots from the lowest Vin that lights the LED - even dimly?  Thank you.
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picowatt

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Re: Is joule thief circuit gets overunity?
« Reply #682 on: April 29, 2013, 12:37:29 AM »
.99,

I just read a portion of your new scopes manual.  It looks like it has an 8 bit native resolution at full bandwidth/max sweep rates, and can do 11bits in hi res mode at lower sweep rates.


PW
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poynt99

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Re: Is joule thief circuit gets overunity?
« Reply #683 on: April 29, 2013, 12:41:33 AM »
A quick sweep of the input voltage and the resulting current trace.

Lawrence to answer your request, you can see in the video what the wave forms look like when the circuit just begins oscillating.

http://www.youtube.com/watch?v=T-E7W8HGucg
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ltseung888

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Re: Is joule thief circuit gets overunity?
« Reply #684 on: April 29, 2013, 12:49:46 AM »
Quote from: poynt99 on April 29, 2013, 12:41:33 AM
A quick sweep of the input voltage and the resulting current trace.

Lawrence to answer your request, you can see in the video what the wave forms look like when the circuit just begins oscillating.

http://www.youtube.com/watch?v=T-E7W8HGucg
@poynt99,
 
I can see a USB in the video.  Can you capture the raw data in that USB?
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poynt99

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Re: Is joule thief circuit gets overunity?
« Reply #685 on: April 29, 2013, 12:52:58 AM »
Yes, I can.

Give me a couple hours to get that uploaded.
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picowatt

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Re: Is joule thief circuit gets overunity?
« Reply #686 on: April 29, 2013, 01:11:59 AM »
.99

Post #264 on page 18 is a better capture shot from lawrence regarding board 33.  Still  bit noisey and much more "spikey" than what your seeing.

PW 

ADDED:  Sorry, that was for board 38, never mind.  My prior posts are for board 33 however.
Did not have the reading glasses on...
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TinselKoala

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Re: Is joule thief circuit gets overunity?
« Reply #687 on: April 29, 2013, 01:36:42 AM »
@.99.... beautyfull! You gotta love the new Tek scopes. The Digital Phosphor idea really makes for a nice looking display.
Two of those probes together cost more than what my car is worth!
Do you by chance have a differential voltage probe and a current probe for it?

I think that scope can probably do two live math traces, so you could display input voltage and current, instantaneous power, and the integral of the power all on one screen.

I also think that it's pretty clear that there is a DC offset issue happening with the Atten scopes at this very high sensitivity setting. 12 mV isn't much and wouldn't show up in most cases.... but there has to be a reason why there's nearly a two orders of magnitude price differential between Atten and Tek, too.
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poynt99

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Re: Is joule thief circuit gets overunity?
« Reply #688 on: April 29, 2013, 01:46:48 AM »
Lawrence,

3 uploads; 001 is for an Input Voltage of about 0.5V, just as the circuit began oscillating. 002 is for an Input Voltage of about 1.00V, and 003 about 1.36V.

Happy crunching.
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picowatt

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Re: Is joule thief circuit gets overunity?
« Reply #689 on: April 29, 2013, 01:48:54 AM »
Quote from: TinselKoala on April 29, 2013, 01:36:42 AM
@.99.... beautyfull! You gotta love the new Tek scopes. The Digital Phosphor idea really makes for a nice looking display.
Two of those probes together cost more than what my car is worth!
Do you by chance have a differential voltage probe and a current probe for it?

I think that scope can probably do two live math traces, so you could display input voltage and current, instantaneous power, and the integral of the power all on one screen.

I also think that it's pretty clear that there is a DC offset issue happening with the Atten scopes at this very high sensitivity setting. 12 mV isn't much and wouldn't show up in most cases.... but there has to be a reason why there's nearly a two orders of magnitude price differential between Atten and Tek, too.

TK,

Yes, but if one knew the low cost scope well, and compensated for its offset and any DC gain error after making a few cal tests, one could still acheive some accurate results (at least better).

I believe I read there was a firmware update for the Atten scopes regarding the "cal on power up" hanging during offset correction.  Don't quote me, but I believe I bumped into that while searching for the DC specs.

But that Tek sure makes pretty outputs...  And at only $9G used...  (probes, taxes, dealer prep, wash wax and a tank of gas not included)

PW
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