On 13 jun, 13:19, Keith Dysart wrote:
On Jun 13, 9:35*am, Cecil Moore wrote:

On Jun 12, 8:52*pm, Owen Duffy wrote:

If there was a valid Thevenin equivalent circuit for a transmitter (and
that is questionable), then you can not use that equivalent circuit to
make any inference about the internal dissipation of the source (the
transmitter in this case), or its efficiency. Nevertheless, I see people
trying to do this one way or another in the various threads here.

In his food-for-thought article on forward and reflected power, Roy
(w7el) says: "So we can model a 100 watt forward, 50 ohm nominal
transmitter as a 141.4 volt (100 * sqrt(2)) RMS voltage source in
series with a 50 ohm resistance." He goes on to calculate power
dissipation in the source resistor.
--
73, Cecil, w5dxp.com

And a mere two sentences back one find Roy writing:
"I make no claim that the model circuit represents what’s going on
inside the transmitter. For one thing, a real transmitter will
typically be more efficient than the model. However, if measurements
and observations are limited to the outside of the transmitter,
the model is very good (within the non-shutdown range). Although
a real transmitter won’t contain the model’s resistance as a
resistor, we will take a look at the model resistor’s dissipation
to see how it interacts with the “reverse” power."

Was your disingenuity deliberate?

...Keith

Hello

Last night I was a little tired when I send my answers to Owen
stinging my eyes. It was too late and time to go to sleep :)
I should tell owen he was inadvertently moving towards a logical
bifurcation's fallacy because is not absolutely true that Thevenin
theorem can not be used to calculate -for example- circuit efficience.
There are an exception to this limitation = It can be used to
efficience calculations when disconnecting the load in the original
circuit the dissipated power is null.

Miguel LU6ETJ