Cecil Moore wrote:
Roger wrote:
If the impedance of the perfect source is zero, what limits the power
output from the source?

Exactly, just make the output impedance zero and the
perfect source will deliver infinite power. Does that
sound like it is related to reality?

I think I would say it differently. I would describe the "perfect
voltage source" as a variable impedance, constant voltage source, with
all the impedance supplied by external loads. To my thinking, to define
the perfect voltage source as having no impedance, and then using "no
impedance" as an excuse to assign a negative reflection factor so that
voltage from another source is inverted, is beyond belief. Not reality
at all, as you say.

I can accept the concept of infinite power, and recognize the
impossibility at the same time. It would do very bad things to a real
circuit!

However, I can see the dilemma faced by a purist who sees 2v from a
reflected wave (because the reflected wave has returned to the source
and reflected as if it were an open end) and the 1v from the source at
exactly the same location. Something must be wrong.

I don't recall any examples using perfect CURRENT sources. I think a
perfect current source would supply a signal that could respond to
changing impedances correctly. It should solve the dilemma caused by
the rise in voltage which occurs when when a traveling wave doubles
voltage upon encountering an open circuit, or reversing at the source.

What do you think?

73, Roger, W7WKB