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Old June 15th 10, 07:36 PM posted to rec.radio.amateur.antenna
Roy Lewallen Roy Lewallen is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 1,374
Default Where does it go? (mismatched power)

Owen Duffy wrote:
lu6etj wrote in news:da3e5147-cad8-47f9-9784-
:

...
OK. Thank you very much. This clarify so much the issue to me. Please,
another question: On the same system-example, who does not agree with
the notion that the reflected power is never dissipated in Thevenin
Rs? (I am referring to habitual posters in these threads, of course)


Thevenin's theorem says nothing of what happens inside the source (eg
dissipation), or how the source may be implemented.
. . .


Cecil has used this fact as a convenient way of avoiding confrontation
with the illustrations given in my "food for thought" essays. However,
those models aren't claimed to be Thevenin equivalents of anything. They
are just simple models consisting of an ideal source and a perfect
resistance, as used in may circuit analysis textbooks to illustrate
basic electrical circuit operation. The dissipation in the resistance is
clearly not related to "reflected power", and the reflected power
"theories" being promoted here fail to explain the relationship between
the dissipation in the resistor and "reflected power". I contend that if
an analytical method fails to correctly predict the dissipation in such
a simple case, it can't be trusted to predict the dissipation in other
cases, and has underlying logical flaws. For all the fluff about
photons, optics, non-dissipative sources, and the like, I have yet to
see an equation that relates the dissipation in the resistance in one of
those painfully simple circuits to the "reflected power" in the
transmission line it's connected to.

Roy Lewallen, W7EL