After discovering the error on Roy's web page at:

http://eznec.com/misc/Food_for_thought.pdf

I have begun a series of articles that convey "The Rest
of the Story" (Apologies to Paul Harvey). Part 1 of
these articles can be found at:

http://www.w5dxp.com/nointfr.htm

Stand by for the other three articles.

On Mar 4, 3:36 pm, Cecil Moore w5dxp.com> wrote:

Looks good. And well presented. There is only one small problem
with the analysis.

When the instantaneous energy flows are examined it can be seen
that Prs is not equal to 50 W plus Pref.

Taking just the second example (12.5 ohm load) for illustrative
purposes...

The power dissipated in Rs before the reflection arrives is
Prs.before = 50 + 50cos(2wt) watts

On Mar 4, 8:00 pm, Keith Dysart gmail.com> wrote:

Keith Dysart wrote:

That is irrelevant. The power (irradiance) model
doesn't apply to instantaneous energy and power.
Hecht says as much in "Optics".

Nobody has ever claimed that the energy/power
analysis applies to instantaneous values. The
energy/power values are all based on RMS voltages
and currents. There is no such thing as an
instantaneous RMS value.

Keith Dysart wrote:

There are no reflections at the source so the reflected
energy flows through the source resistor. There is no
interference to redistribute any energy. There is no
other place for the reflected energy to go.

Cecil Moore wrote:

Interesting.

Do you also use only the RMS phase and RMS interference to come up with
your RMS answers?

8-)

On Mar 4, 10:25 pm, Cecil Moore w5dxp.com> wrote:

Are you saying that conservation of energy does NOT apply to
instantaneous values?

On Mar 4, 10:27 pm, Cecil Moore w5dxp.com> wrote:

That is the conundrum, isn't it?

And yet the analysis of instantaneous energy flows definitely
shows that the reflected energy is not the energy being dissipated
in the source resistor.

Encountering this conundrum, and not wanting to give up on
conservation of energy, is what helped me form my views on
the nature of reflected energy.

...Keith

Keith Dysart wrote:
...

What if the source resistor is of finite length :)
Alan

On Tue, 4 Mar 2008 17:00:31 -0800 (PST)
Keith Dysart gmail.com> wrote: