Without further ado, let me share with you -- inviting comment -- the most interesting result of yesterday's (4 March 2011) tests at the University, using a Tektronix 3032 scope.
Here I am using the eJ toroid that I wound. I began with a Jameco toroidal inductor (100 uH, Jameco part # 386601), and wound fifteen windings bifilar of 22-gauge insulated (one with plastic, the other enamael) copper wire. The inductance of EACH of my windings came out to 24 uH. The Jameco winding is not involved in this test run, and the wires are left unconnected from this winding (which would be the secondary winding for a Tseung-type system).
I have given results with this SAME eJ toroid above... where we observed Pin as a simple sawtooth and Pout a single hump or spike. Now -- please look closely at the waveforms for this run at 0.996 V (in from the power supply), in the attached.
First, we look at the detail for roughly 1.5 cycles in the first attached screen-shot. The red Pin waveform is approximately what we have seen before, a saw-tooth pattern. But the (red) Pout waveform is quite different!
Instead of a single hump or spike essentially bounded at zero-power as we have seen in the past, we now see a U-shape that significantly OVERSHOOTS ZERO, demonstrating current and voltage Out of Phase, as we also see comparing the voltage across the (LED+transistor) in yellow, and the current in the 1-ohm CSR shown in blue.
Further, notice the oscillations/wiggles in the waveforms for the output power and voltage waveforms. Very interesting. To me, this is striking and rarely-seen behavior, and I have been working with these types of circuits for months now.
To get the efficiency with some accuracy, we have the Tektronix 3032 calculate Mean Power for both Pin and Pout over numerous cycles -- with this interesting result:
n = 44.8 / 39.8 = 1.13 = 113%
+- about 3% as previously noted. If you are visually comparing Pin and Pout waveforms in the attached, note that the scale in the screen display for Pin is 20 mVV whereas the scale for Pout is 50 mVV (which does not change the result above), which I did because the Pout curve was getting clipped on the 20mVV scale as i recall.
In order to encourage and facilitate comparisons, I include a final attachment which shows Pin and Pout for these data at 0.996V juxtaposed with the data for the same eJ toroid ran at nearly the same voltage (0.993 volts), but where the latter displays the "normal" pattern with just one spike. The two waveforms in the center of this attachment (trace 2 and 3 ) give Pout and Pin both on the same scale, 50 mVV, to make visual comparisons more straightforward for you. If you think the Tektronix 3032 may be making a mistake when calculating the Mean power in the case where the power is sometimes negative and sometimes positive, I invite you to evaluate the areas under the Pin and Pout curves for one cycle, subtracting the opposite-signed power region, and then evaluate n from this integral (that is, using n = Ein/Eout, as I have demonstrated before). It would be a worthwhile check. I have done this roughly, and the Tek 3032 calculation seems good.
You have a dozen questions? I have many also...
After seeing this result, I returned twice to the same circuit and getting the voltage as close as I could, but could not generate the unusual "spiky" Pout waveform again in the limited time I had on the Tek 3032 at the University. And those results came out with COP = n of about 90%.
I recall having seen such a waveform at home before, but I do not know just how to reproduce this spiky waveform -- wish I did. And I am very open to suggestions.
I will say that I looked first at the many-cycle Pout (attached), then looked at many-cycle Pin (moving the channel-1 probe to do so), then moved the channel-1 probe back in order to re-measure Pout and record the approx detailed Pout waveform (attached). The Pout waveform remained the same over the several minutes required to do these measurements and record them on the computer, about 15-20 minutes. So however I got in this mode, with the unusual waveforms, zero-crossing Pout and COP evidently greater than one, the condition remained for a while.
When I saw that n was coming out larger than one, I was a bit excited and did go back and get the detailed waveforms recorded. However, I was thinking that I could simply come back later and get more data at this condition after running at other voltages, which was not the case yesterday afternoon -- I'm glad I got as much data as I did and recorded it for you all to see.
Now the question is -- what does this all mean? and how can one get back to this out-of-phase relationship between V and I in the output circuit?? (I have reported this condition before as you may recall, some time ago, but that was with the LT-type circuit and this is a simple JT.)
To me the result is striking and noteworthy and something of a breakthrough. But can it be repeated? Repeatability is a core requirement for solid science and progress.
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Topic: LTJT - poynt99 Tests #2 (Read 106233 times)
