On Sun, 8 Jun 2008 16:16:56 +0200, "Antonio Vernucci" wrote:

Since E/I is simply a ratio, R is also a ratio. And we know that a ratio
cannot dissipate power, or turn
electrical energy into heat, thus the output resistance R is non-dissipative.
I have made many measurements
that prove this.

Walt, W2DU

Hello Walter,

thanks for your explanation.

I remember having read your excellent articles on QST magazine many years ago,
in which you also explained, among many other things, why reflected power cannot
dissipate in the final stage of a transmitter.

I am not at all opposing your explanation of "non disspative resistance" (on
the other hand how may I contradict a person named Maxwell, hi), but I have some
difficulties to appreciate it.

In my understanding resistance just means that current and voltage are in phase.

There are two possibilities for this to occur:

1) dissipative resistance. Example is a pure resistor, in which power is
converted into heat.
2) non-dissipative resistance: Example is a DC motor, that converts electrical
power into mechanical power. An ideal motor would convert all absorbed power
into mechanical power, producing no heat

But I am unable to see how the second case could be fitted into the transmitter
model.

Thanks and 73

Tony I0JX - Rome, Italy

Hi Tony,

The reason a Class B or C amplifier can have efficiencies greater than 50 percent is because the output source
resistance at the output of the pi-network is non-dissipative, as I said in an earlier post. I realize this
phenomenon is somewhat difficult to appreciate. However, I have explained it, and proved it with measurements
reported in Chapter 19 in Reflections 2. I have explained it further in an addition to Chapter 19 that will
appear in Reflections 3, which has additional proof from measurements made since the original Chapter 19 was
written.

This addition to Chapter 19 is Chapter 19A, which I asked Cecil to put on his web page for all to see. Just
scroll down to Cecil's post to see "Chapter 19A from Reflections III", and double click on the url. You will
see the entire Chapter 19A. Apparently you don't have a copy of Reflections 2, so I'm going to email you a
copy of the original Chapter 19. I hope these papers will help in understanding why the output resistance of
the pi-network is non-dissipative.

Walt, W2DU