Is joule thief circuit gets overunity?

[picowatt]

@picowatt

The pictures on reply 450 were wrong because I did not press the "default setup" button first before doing the calibration.  The Atten Oscilloscopes have many options and settings.  For normal operations, I had to use specific settings depending on what I wanted to display.  For example, I displayed Ch1 Vpp, Vrms and Ch2 Vpp, Vrms, etc.  To do the calibration of the probes correctly, very specific setting was required.  The Atten Scope has the "default setup" or "factory setup" to help to achieve that.

I did not press that button first and thus the "calibration pictures" were wrong.  A simple error.

*** This is actually a good experience.  When I bring my Atten Scopes (or use new ones) at one of the Top Universities, I shall do the full calibration procedure in front of the Academics.  The results will be more convincing.  It also points out the difficulty if I rely on "their oscilloscopes".  There is no possibility that I will be able to master the operations of all different models of oscilloscopes.  Bringing one or two Atten Scopes for demonstration is a MUST.  (Bringing a laptop computer is NOT.)

The signal at the calibration post is a 1 K square wave of approximately 3Vpp.  It doesn't matter what the scope's timebase or vertical sensitivity is set to, your scope should always indicate approximately 3Vpp when the calibrator is probed (assuming the probe and channel probe factor settings are correct).

If at anytime you when you are using your scope, you probe the calibration terminal with any probe connected to any channel at any vertical sensitivity or timebase setting, and the display is anything other than approximately 3Vpp, something is wrong.  You should not have to be in "default setup" to make the scope read correctly.

Besides incorrect probe compensation, your post 450 scope 1 channel 2 shows the 3Vpp cal signal as being 15Vpp.  Does this mean that all of your input current measurements made with scope 1 channel 2 were being indicated as 5 times higher than they actually were?  How did you have the scope set so that channel 2 reads higher than it should by a factor of 5?

I suggest you recheck all probes and channels using the calibrator post to ensure that all channels are indicating approximately 3Vpp, adjust your probe compensation for minimal under/overshoot and then repeat a few of your tests.

To lend validity to any further scope shots of your JT circuit, I suggest you also provide scope shots of the probes connected to the cal terminals as you have the scope set to make your JT measurements (adjust only the vertical sesitivity if needed to prevent display clipping).

The very fact that you would post the scope shots of 450 in response to TK's request to see your probe compensation  without realizing the errors contained in those captures is in itself quite telling.   

PW

       

[TinselKoala]

The correct Oscilloscope Probe Calibration diagrams.

@TK,

I read the Manual and found the correct Oscilloscope Probe Calibration Procedure.  The correct photos are shown here.  Thank you for all your comments - they refer to incorrect photos.  All my posted data are correct as the calibration was done right for me when I bought the Scopes.

@testers and All researchers.

False Alarm from TK.....  I did not give him the correct calibration diagrams.....  The pictures on reply 450 are definitely not calibration pictures.  Should not blame TK for not recognizing them as oscilloscope manufacturers have different displays.

Lawrence, your protest here is simply wrong. You are grasping at straws in an attempt to get yourself out of this major error. False alarm from me? No, dear Sir..... the story is somewhat different.

You provided what I asked you for, which was the traces from the scope's calibrator output without making any adjustments to your probes. This means that the traces you showed in post 450 ARE INDEED traces which reflect the conditions of your probe/channel combinations as you have been using them. Is this, or is this not, the case?

The fact that you have NOW calibrated your probes according to the first chapter of your owner's manual... or at least one of them... after all this time.... is rather "telling", as Picowatt might say. How long have you had your manual?

Your owner's manual instruction is garbled somewhat though: Your probe/channel combo must be calibrated together. Not just "channel 1 factory settings". You manually set your channel vertical atten to 1 volt/div. You assure that your probe switch is at 10x and that the channel setting is also at 10x internally. You manually set your timebase to read conveniently for a 1 kHz signal. You assure that you are triggering on the channel of interest and at the correct voltage level and rising or falling slope. Then you probe the scope's calibrator output with the probe/channel combo you are calibrating. You carefully adjust the probe's compensating capacitor until you get the nicest looking square wave, and on analog scopes you adjust the channel attenuator knob's "cal" portion to make the displayed waveform show exactly three divisions (three volts), or whatever its calibrator output is supposed to be.  You repeat this process for each channel/probe combination. Generally, the channels themselves will be "equal" in input capacitance, and once the probes are set properly they should not require resetting much and it shouldn't matter which probe you have in which channel, on a given scope/probe set. But just in case, for my own two in-use scopes, I use only one probe set for one scope and the other for the other scope, and I have them all marked 1,2, and A,B, so they always go in the same channels in the same scopes.

Since the traces you showed in post 450 seem to reflect the conditions under which your data were gathered.... you need to calibrate, fix the voltage problem, and redo your experiments and calculations. You may still find your OU results.... I don't think this is the only error.... but this much, at least, must be done.

I pointed out the discrepancy in voltage on one of your traces some time ago, or rather I "asked" if anyone noticed anything peculiar, and .99 came back with the abnormally high voltage, but nobody made any further comment about it.

All my posted data are correct as the calibration was done right for me when I bought the Scopes.

And that is probably why ONE of your probes has correct compensation. Whoever did it, used the instructions in the manual, which only cover one probe in one channel. SO all your posted data FROM THAT ONE SINGLE PROBE/CHANNEL COMBO may indeed be correct. Or it may not. Only redoing the experiment will allow you, or us, to tell.

Should not blame TK for not recognizing them as oscilloscope manufacturers have different displays.

Further.... you, Lawrence, should not presume to attempt to teach me about oscilloscope displays or the usage of oscilloscopes in general. I asked you for something specific and you supplied it. Now, you are weaseling, because your ignorance and your misuse of the scopes is made plain for all to see. Your only possible "out" is to prove that the scope shots in 450 were not taken recently but were taken before your experiments, and the problems shown were corrected before you began taking data. But that's not the case, is it.

[ltseung888]

Board 80 results after all probes were recalibrated.  Same characteristics.  can wait for poynt99 and Physicsprof to post their results with their oscilloscopes.

[TinselKoala]

Now your "Board 80 input" looks like you have the current sensing probe hooked up backwards. The voltage drops indicated on the top trace reflect the times when the oscillator is drawing the most current from the battery, so these instants should be reflected by +peaks+ not drops in the current trace. Your trace doesn't represent "negative input power", more likely it represents a probe hooked up backwards or a channel not properly inverted for the measurement hookup your board requires.

And it's clear from your "Board 80 output" that you will no longer have any negatives in your output result, as all your measured values in both traces are now positive.

I think it's pretty clear to anyone who can read a scope trace that your results are now going to be considerably different.... now that you have properly calibrated ALL your probes. Yes, you do need to retract and redo your previous results, because THEY WERE DONE INCORRECTLY. This is an issue of scientific integrity here, Lawrence. You took data with uncalibrated probes with substantial artefactual errors, and you recorded and reported that data as correct, when it was not. A retraction is indeed absolutely in order. If a redo still supports your claims, that's fine, at least you did the right thing. If the redo doesn't still support your claims, then we have saved a lot of people a lot of trouble trying to replicate your errors that you published as correct.

Now.... the input current trace in your recent example Board 80 shots. You are here measuring a very small signal at the scope's high gain setting. I asked you before: Do your scope traces change AT ALL as you move cabling around to different locations? I don't mean moving the probe points, just the way the cables themselves are routed from the board under test, over to the oscilloscope. Often, at high gain settings reading weak signals, the system can be very sensitive to how wires are routed, and even the length of the probe's ground cliplead can affect readings greatly, especially for signals like yours with substantial high-frequency components (the spikes).
So please, set up as normal, look at the current trace as in the post above, and move the probe wires around while measuring. Does the waveform change at all?

[TinselKoala]

Lawrence, do the two slides below show your input current and voltage measurement positions that you have been using for your recent data? Why do they not agree with the circuit diagram?

Just to be clear: The circuit diagram has the common ground for all four channels on one side of the input current viewing resistor, away from the battery, as is correct. It shows the probe tip (incorrectly called "+ve" in the caption) of the current channel connected to the battery-resistor connection, as is correct to make this measurement, and the reference or ground lead (incorrectly called "-ve" in the caption) connected to the common ground.

But the photograph shows this probe reversed, with its TIP connected to the circuit common ground and the reference lead connected to the battery-resistor junction. This of course inverts the signal -- shows it going backwards -- as well as introducing a magnitude error into the current reading, especially if you have another probe hooked up _correctly_ to read the input voltage.

Please explain this discrepancy, which to my mind would fully account for your anomalous "negative" input power computations that you have recently been reporting.