WW,
Regardless if the metering circuit has emf induced into it or not the metering circuit either segments or sectors the loop (if on the inside) or becomes another loop in addition to the secondary loop(if on the outside).
I don't know what you mean by "inside" and "outside".
Yes, solenoid length will have pronounced effects and there is a point where an extended loop may see 'up' and 'down'. I feel those issues are going beyond the initial experiment.
They go beyond the original experiment, yes. But the issue you have seems to be with the decoupled measurement technique I use.
I keep saying 'view from above' - 'in your mind's eye'. If nothing else, when you have the metering circuit crossing over the solenoid (decoupled, if you choose) stand on the table and look directly down at the top of the solenoid and loop. Forget the height differences for a moment and imagine the whole experiment is in 2D. The metering leads cut across in some fashion. Even though they are not the subject of induction they change the Gaussian surface area. They don't need to be on the same plane.
You really believe that a very slight angle (3º max) is going to skew the measurements and/or induced emfs that much?
You are saying that it is truly an amazing coincidence that the decoupled measurements of all the summed emfs equals exactly and oppositely the summed voltages across the resistors? Is it also an amazing coincidence that the decoupled measurements across the resistors equals exactly the measurements across the resistors taken in-plane? Is it yet another amazing coincidence that my simulation of this experiment also predicts exactly what I measure between
all points on the loop using the decoupled measurement technique?
As you now see, the angle of the metering circuit does matter. Why? Because changing the angle changes the Gaussian surface area of both sections of the loop now sectioned by the metering leads.
I'm sorry, I don't see a significant effect on the experiment from the 3º angle at all.
This is why I say there is no way to connect a metering circuit without changing something in the experiment.
Then I challenge you to explain those amazing coincidences I outlined above. I say the detrimental effect (if any) is undetectable and/or insignificant to the results.
Does your above statement apply to ALL measurements? What is that
change you speak of? How big is that change (i.e. quantify it)? Do the scopes and leads in Lewin's experiment invalidate his results too?
The voltages you are seeing are the voltage induced on one loop minus the voltage of the other loop (because the original loop is now segmented or sectored by the metering circuit.
Assuming you are referring to a decoupled measurement, what the probes are measuring is representative of precisely what voltage (both emfs and potential differences) difference there is between any two points on the loop. It exists whether the measurement probes are there or not.
The same voltages you are measuring have very little to do with the resistors.
I don't know what you mean here.
If the resistors were equal in resistance, even down to zero Ohms, and you measured from original points A to D you will see .5V. The reason, both sectors of the original loop now have 1V induced into each of them.... At the joining conductor (the metering circuit) what little voltage is seen is the result of two opposite polarity 1V induced into each segment.
Equal value resistors (reasonably larger R than Rwire) would not yield a decoupled measurement of 0.5V between D and A. My calculation indicates that 0V will be measured in such case. The reason is very simple; we know the total emf is 1V, we know that emf = PD, and we know that half the PD is across each resistor. So when you do your KVL around half the loop from point D to point A (same answer for BOTH directions), we have: -0.25V + 0.5V - 0.25V = 0V.
Now for the case with no resistors at all, i.e. a closed loop with a uniform wire, I'll let you guys ponder that one (as I have) as to what voltage would be measured half way across the loop. Show your work.
The only reason .4V was seen between A-D was because the resistors skewed the angle of the metering leads. Your 'normal to the loop' metering circuit was normal to the loop only in a mechanical sense.
0.4V is seen between points D and A with the original value resistors, for the same reason we see 0V with equal value resistors. The KVL sum again works for BOTH directions. Starting from A going up the left side across the 100 Ohm we have: 0.25V -0.1V + 0.25V = 0.4V
Since my above description is exactly how angular position sensors work (as explained in the Maxim Application sheet brought up early in this thread) I really don't feel I need to argue the point.
I would caution against relying on MAXIM's theory in that paper of theirs, they made errors as well. For one eg. they claim that all the emf is induced in the resistors. Of course that is completely opposite to the truth. They don't fully understand the physics behind this apparatus even though they can get it to work.
It would be a great thing to share the understanding but that didn't work for me when it was 'shared'. So, I can't blame you if you choose another path.
The only path that interests me is the one that leads to the truth. I would hope that would be the case for all.
I look forward to your responses.
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Topic: Professor Walter Lewin's Non-conservative Fields Experiment (Read 312196 times)
