Current through coils
Cecil Moore wrote:
John Popelish wrote:
I am still having a bit of trouble visualizing how the coil was
instrumented and terminated to get this result. I am also a beginner
when it comes to S parameters.
I think Tom did what I did the other night. I hooked the coil
across my IC-756PRO's output, used minimum power, and tried
to supply 4 MHz power to the 4+j1250 ohm coil that I have.
It naturally rejected (reflected) virtually all of that power.
I found, as Tom did, that the standing wave current at both
ends has virtually identical phases but that is already known.
The delay through the coil simply cannot be tested in that
test arrangement. Tom just repeated Roy's experiment of a
few years ago and obtained the same meaningless results.
So did I so I didn't even bother to report them.
My reservation with you and few others is your emotional
investment in being correct. It makes your opinions less
trustworthy.
Whoa there, I just made a mental blunder about radiation
resistance and readily admitted it. My emotional investment
is in fighting falsehoods, myths, and old wives' tales.
That's all.
But the goal of such "fights" should be altering other's opinions.
How's that been working out for you? ;-)
The test method for determining the delay through a piece
of transmission line or a coil is the same as it has been
for more than a century.
Have you got a reference to a Bureau of Standards bulletin on this
method to measure inductive current delay? It doesn't work for
filters made of lumped inductors, capacitors and resistors.
Otherwise, there would not be special designs that sacrifice other
properties, to keep delay almost constant as frequency changes.
Wait a second, an inductor at resonance is a filter made of
inductance, capacitance and resistance (and transmission line
effects). Hmm.
Find the 1/4WL self-resonant
point and calculate the delay. Other methods, resulting
in far different results, are obviously invalid.
"Obvious" must be something in the eye of the beholder.
If a 2 port device (Are there really any perfect 2 port devices that
don't have an implied 3rd port?) involves only a single energy
transport mechanism from one port to the other, this is a bit closer
to obvious. But if the device uses competing, parallel energy
transport mechanisms (EM waves, inter turn capacitance, mutual
inductance, etc.) it is less clear that the combination of energy
transport effects has a constant delay effect on a current wave as
frequency changes.
|