On Jan 3, 7:22*am, Roger wrote:
Keith Dysart wrote:
On Jan 1, 9:03 pm, Cecil Moore wrote:
Roger wrote:
The principles of superposition are mathematically usable, not too hard,
*and I think very revealing. *Yes, if we use part of the model, we must
use it all the way. *To do otherwise would be error, or worse.
Roy and Keith don't seem to realize that the zero source
impedance for the ideal voltage source is only when the
source is turned off for purposes of superposition.

I am not sure you have the methodology quite correct.
The source is not turned off; its output is set to 0.

It does what every ideal voltage source will do when
set to a voltage; maintain that voltage. Through all
of this, the impedance of the ideal source remains 0.

Now it turns out that an ideal voltage source set
to zero volts can be replaced by a short which also
has an impedance of 0 and produces no volts. But this
does not alter that the ideal source always has an
impedance of 0.

Analogously, an ideal current source always has an
infinite impedance. When set to 0 amps, it behaves
exactly like an open circuit.

They
conveniently avoid turning the source voltage on to complete
the other half of the superposition process. When the
source signal and the reflected wave are superposed at
the series source resistor, where the energy goes becomes
obvious. Total destructive interference in the source
results in total constructive interference toward the load.
See below.

You have been a supporter of this theory for a long time.
Yes, I have. I am a supporter of the principles and laws of
physics. Others believe they can violate the principle of
conservation of energy anytime they choose because the
principle of conservation of energy cannot be violated -
go figure.

You should really stop repeating this to yourself. No
one is attempting to violate the principle of conservation
of energy.

By continually repeating this mantra, you convince
yourself that you do not need to examine the claims
of those who disagree with you. So you do not
examine and understand their claims. This seriously
limits your capability to learn.

If you truly wish to demolish the claims, you should
study them in great detail, then write an even better
and more persuasive description of the claim than did
the original author. Then identify and point out the
flaws.

As it stands, you do not examine the claims, but
immediately coat them with the tar of "violates
conservation of energy" or some other mantra and
walk away.

It does not lead to learning.

...Keith

I fully agree with the philosophy you express here Keith. *But I can see
* how you would doubt that I am practicing what I just agreed with.

You may have mis-interpreted my comments. I have NOT
seen evidenace of the behaviour I describe above in
your writings.

The comments mostly apply to a single poster who has
been posting on this group for many years, at least
since when I first started viewing this group in the
mid 90s and began to really gain an understanding of
transmission lines.

The presence of this poster providing misleading
information makes this group a rather unique learning
environment.

In most learning environments, the information is
neatly packaged and presented from a consistent
point of view with no challenge.

Here, a lot of chaff is mixed with the wheat. This
has the "benefit" of forcing the learner to
understand well enough to make decisions between
competing explanations. The learner who makes the
right choices comes out with a much more solid
understanding than one who has just been (spoon)
fed the story. On the other hand, some have
probably been lead seriously astray.

For sure, I have a better understanding than
I would have had without the challenging
misleading information.

So for sure it would be better for the poster
in question were he to let go of some of his
incorrect beliefs, it would also reduce some of
the opportunities for learning provided to
others lurking or partaking in the discussions.

...Keith