Peter O. Brackett wrote:
Roy:
[snip]
"Roy Lewallen" wrote in message
...
Not QED at all. You claimed to have proved that maximum power is
delivered to a load when a transmission line is terminated such that the
reflected voltage on the line is zero.
[snip]
No I did not! Never said that, never have. Where did you get that idea?
This is from your posting of August 25:
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Roy:
[snip]
No one from "Camp B" has given any justification for the assumption that
the condition for minimum reflection is the condition for maximum power
transfer. We're lacking either a proof, a derivation from known
principles, or even a numerical example. I maintain that this assumption
is false.
[snip]
I did just that in a separate posting on this thread a couple of days ago.
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Then on August 26, I posted:
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. . .
I'll restate something I mentioned before (first incorrectly, then
corrected). Connecting a load to a transmission line which is the
complex conjugate of the transmission line Z0 does *not* guarantee
maximum power delivery from the source, or to the load. The load
impedance which provides maximum load power is the complex conjugate of
the impedance looking back from the load toward the source. That
impedance is the source impedance transformed through the transmission
line between source and load, and it's not generally the same as the
line's Z0, or its complex conjugate. When this condition of maximum load
power is met, there will almost certainly be voltage and current wave
reflections on the line -- there would be none only if the optimum load
impedance coincidentally happened to be equal to the line Z0. So the
argument that there can be no reflection of the voltage wave under the
condition of maximum power transfer is wrong.
You didn't show differently in your analysis, and no one has stepped
forward with a contrary proof, derivation from known principles, or
numerical example that shows otherwise.
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To which you replied, also on August 26:
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Yes I did. I guess that you missed that post.
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I haven't been able to find this proof in your postings.
I said that for a general complex Zo the reflected voltage is generally
NOT zero at maximum power transfer.
Well, shoot, I agree with that, as I always have.
. . .
BTW...
Aside: From the postings of Dave and yourself along this thread, I get the
impression that
ya'll beleive that lumped systems obey different laws and should should be
modeled
differently than distributed systems. I am surprised by that claim. Surely
you don't mean that!
I believe you can build a bad or inappropriate model with lumped or
distributed components, and draw invalid conclusions from them. Perhaps
you missed my posting a day or two ago where I pointed out that your
model using lumped components was clearly not the same as one using a
transmission line, by means of the very simple test of observing the
current in a load resistor.
And yes, lumped systems should generally be modeled differently than
distributed ones.
Surely all electrical systems, lumped or distributed, must obey the laws of
electrodynamics as set
out by Maxwell-Heaviside. Do you know of any cases where they don't?
This argument of "you don't agree with my view of how things work, or my
inappropriate models, therefore you don't believe in the Laws of
Physics" is as tiresome as it is pompous.
Roy Lewallen, W7EL
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