On Dec 24, 9:26*am, "Dave" wrote:
"Keith Dysart" wrote in message

...
On Dec 23, 10:12 am, "Dave" wrote:

Are you really prepared to throw away P = VI?

yes, when the V and I are the superimposed voltage and current that you
insist are the real current and voltage on the line.

They are the real current and voltage. I can measure them
with voltmeters and ammeters.

Directional wattmeters measure the real current and
voltage and perform some arithmetic on these measured
values to display "forward power" and "reflected power".

"Forward and reflected power" are derived from the
real voltage and current.

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.

try to look at it this way. *when you look at the forward and reflected
waves separately it is intuitively obvious how the power calculation shows
the flow along the line with each wave. *however, when you look at standing
waves you get spots every 1/4 wave where either V(x,t) or I(x,t) is ALWAYS
zero... by V*I this means the power at that point is ALWAYS zero. *since
power is just the measure of the flow of energy, and energy can neither be
created nor destroyed then in the traveling wave there can be no energy flow
past those points. *where it is obvious from the individual Vf(x,t) and
Vr(x,t) or If(x,t) and Ir(x,t) that are ALWAYS related by Z0 at every point
on the line that power does flow both directions. *an obvious contradiction

Absolutely. And many readers resolve the contradiction in the
wrong direction.

And then are willing to throw away P = VI.

and if you can't see it by this point i give up.

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?

i want to throw away this falicy and replace it with the real physically
correct calculation.

Throwing this away will invalidate much.

only in your mind.

I have said it enough times now, and hate repeating myself... so you can
live with your poor misguided assumptions and formula. *i have shown the
obvious errors

I'd suggest that remains to be seen.

...Keith