Is joule thief circuit gets overunity?

[MileHigh]

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

[poynt99]

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.

[poynt99]

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.

[picowatt]

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

[picowatt]

.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