RadioBanter - View Single Post - Rho = (Zload-Zo*)/(Zload+Zo), for complex Zo

September 19th 03, 02:23 AM

wrote in message ...

Its not. Its 3.8 volts, which is entirely consistent with circuit
theory and 'classic' rho. Not only is it higher than the incident
voltage, it is higher than the source voltage.

Ok, now take the capacitor off, and measure the voltage at the end
of the inductor. What do you get?

Not possible for me. My scope probes are in the order of 15 pf, which
is signifcant for this experiment.

Afraid to measure it, eh? Go ahead, we can ignore the 15 pF for now, as
the
load was 100pF. What do you get?

But try using classic rho and revised rho to predict the results for
a shorted load (Zl = 0). Only classic rho gives a reasonable result
for voltage and current.

Classic Rho gives -1, which is a short, and conjugate Rho gives
+1j, which is ALSO a short.

Hint: What is the center of the Smith Chart when it is normalized
to Zo=50+j200?

Not really. A rho= -1 means something else with a complex
Zo.

Hint: What is the center of the Smith Chart when it is normalized
to Zo=50+j50?

Let's review. Two competing proposals (classic and revised rho) were
used to predict the outcome of an experiment. The experiment was
performed; the results resoundingly in favour of classic rho.

I disagree. You need to answer the "hint" question.

Plus, you never measured the Vi (incident voltage wave) coming out of the

inductor, which is what you would use for the voltage RC.

Are you questioning the scientific method or just the results of
this experiment? If the former, the discussion should probably
move to a different group; if the latter, you are invited to
replicate the experiment and demonstrate that an error was made.

I question your methods and your calculations.

I will try the experiment when i get the chance.

Otherwise, there is no reasonable choice except to accept that
classic rho correctly predicts the reflected voltage.

...Keith

Are you saying that a capacitor can reflect a RMS voltage wave that
is greater than the incident voltage wave that charges it?

Hint: What is the center of the Smith Chart when it is normalized
to Zo=50+j200?

Slick