On Dec 24, 1:28*pm, Cecil Moore wrote:
Keith Dysart wrote:
Except that V(x,t) and I(x,t) are not, in general, related by Z0.

*From "Fields and Waves ..." by Ramo & Whinnery, 2nd edition:

V(x,t) = V*e^j(wt-kx) + V'*e^j(wt+kx)

I(x,t) = [V*e^j(wt-kx) - V'*e^j(wt+kx)]/Z0

You are quite unfair to Ramo & Whnnery when you quote them
out of context. It makes them look like they do not have a
clue.

Just because you find the same string ["V(x,t)"] in their
text does not mean that they are talking about the same
thing. (It better not in this case, or you should throw
their book away.)

You, yourself, have made the point in other posts that
the current and voltage on an open circuited line are
in quadrature, so they can not be in the ratio of Z0.

No. The two wave view is merely an alternate set of expressions
which, when summed (i.e. using superposition), provide the actual
voltage and current on the line. These alternate expressions are
obtained by algebraic maniupulation of the more fundamental
descriptive equations.

Methinks you are confusing cause and effect. The standing
wave is not the cause of the two traveling waves.

Of course not. "Standing wave" is just a short hand description
of the distribution of voltage and current on the line.

In my analysis, P(x,t) = V(x,t) * I(x,t) is the equation that means
the power at any point and time can by obtained by measuring the
actual voltage and current on the line at the point and time of interest..

Make that the *NET* power and you will have it nailed.

Are you sure you want to throw away this ability? Are you sure you
want to claim that instantaneous power can NOT be obtained by
multiplying the instaneous measured voltage by the instanteous
measured current?

When the instantaneous voltage is the sum of two more elementary
voltages (same for current) then you are reporting the *NET*
results, not the underlying component results. The *NET* results
do not dictate reality.

Sorry Cecil. The observed voltage and current on the line
are the reality.

...Keith