Re: Current through coils

Cecil,

I have lots of flaws, most of them unrelated to RRAA. But a lack of understanding of fundamental physical laws is not one of them.

Two points, and I won't carry on further.

* Who said anything about "steady state"?

* Current is generally accepted as the flow of charge. (If you know some other definition perhaps that is part of our disagreement.) When the current is different at the ends of a simple two terminal device then the charge flow is different as well. Since charge cannot be created or destroyed (I hope you have no argument with that) then it must be stored or depleted somewhere in that two terminal device. We most likely don't have chemical reactions going on in that device so the charge storage is facilitated through capacitance.

That is what Reg said. You disagreed. Reg is correct.

(No one is discussing power, phasors, degrees, distributed models or anything else you expounded on. Save it for another day.)

73,
Gene
W4SZ

Cecil Moore wrote:
Gene Fuller wrote:

I have no issue with the use of network theory, reflection coefficients, standing waves, or any other commonly used descriptions. However, none of these mathematical conveniences change the fundamental physical laws. If current, and therefore charge, appears to be unbalanced, then there must be charge storage somewhere.


Gene, the flaw is in your misunderstanding of the
fundamental physical laws, not in those laws.

We measure the net current at one end of a coil at 0.1
amp and we measure net current at the other end of the
coil at 0.7 amps (my web page example). The net current
*APPEARS* to be unbalanced, but appearances can be
deceiving. THERE IS NO STEADY-STATE CHARGE STORAGE
ANYWHERE IN THE SYSTEM. Does this violate any fundamental
physical laws? Of course not. Here's why (neglecting losses):

V*I*cos(theta) equals the same power at both ends of the
coil. That proves there is no steady-state energy storage.

V1*(0.7)*cos(theta1) = V2*(0.1)*cos(theta2)

This is a distributed network. A lumped circuit analysis
fails miserably when you try to use it in a standing-
wave environment and you have just proved it. That is
also the same mistake that W8JI and W7EL have been
making.

The forward current at the 0.7 amp point is 0.4 amps at
zero deg. The reflected current at the 0.7 amp point is
0.3 amps at zero degrees. The net current is the phasor
sum of those two component currents.

Inet = (0.4 amps at zero deg) + (0.3 amps at zero deg)
Inet = 0.7 amps at zero deg

The forward current at the 0.1 amp point is 0.4 amps at
82 degrees. The reflected current at the 0.1 amp point is
0.3 amps at -82 degrees. The coil causes an 82 degree
phase shift in both forward and reflected currents and
since their phasors are rotating in opposite directions,
the sign of their phase shifts are opposite.

The net current at this end of the coil is:

Inet = Ifor + Iref
Inet = (0.4 amp at 82 deg) + (0.3 amp at -82 deg)
Inet = 0.057 amps + 0.043 amps = 0.1 amp at zero deg

The fundamental physical laws are perfectly valid as has
been demonstrated here. It is your understanding of them
that seems to be the problem. You seem to have been fooled
by appearances and as a result, you chose the wrong model
with which to try to solve the problem. The distributed
network analysis was developed because the lumped circuit
analysis falls apart under certain circumstances. One of
those circumstances is the presence of standing waves like
the ones that exist in a 75m mobile antenna.
.

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