OK, my point is (and you can test this yourself), that (1) the concept of Rs
is invalid for a class C stage, because it's not a linear device. You can
fool yourself into thinking it is, but it's not. (2) the typical RF output
stage, sans output filter, which consists of a transistor fed by a choke or
transformer and which pulls the collector voltage nearly down to the emitter
acts like an RF voltage source with a fairly low series resistance. I've
_done_ this. I've _measured_ this. I've _burnt_ transistors.

You _can_ get much more power from your output stage than it's "normal"
output power, for that brief (and often shining) moment before the output
transistor lets the smoke out and reverts to the sand and basic
petrochemicals from which it was originally made. This is how you know that
you aren't running it at the Rs = Rl point -- rather, you're running it at
the point where the junction temperature of the transistor is kept to a
level that will let it stay a transistor for a satisfying amount of time.

This is why in my original reply I compared the output amp to a wall socket.
The equivalent Rs of your average wall socket is probably on the order 1/2
to 4 ohms (on the low end for 120V, high for 230). Since I live in the US
and have fairly good feed, I'll use the 1-ohm 120V case, and I'll match Rs
with Rl. Lessee. 120V, 1-ohm, that's 14400 watts -- good! But my circuit
is only is only good for 15 amps and I'm asking for 120?!? Dang! What
happened to the lights?

So you see, every time you plug anything into the wall, you're failing to
match Rs with Rl, and that's a _very_ good thing. It's for exactly the same
reason that you don't match Rs with Rl in your output stage.

"Paul Burridge" wrote in message
...
On Sun, 04 Jan 2004 15:44:04 +0000, Leon Heller
wrote:
-- snip --
My - admittedly little - understanding of the situation is that the
power transferred into a resistor (regardless of power level) will be
maximised when Rs=Rl,. whereupon half the power is dissipated in the
final device and half in the load. Tim's posts seems to refute this
basic truism. Clearly the statement that the output power should be
inversely proportional to the load resistance *must* be false.
--

"I expect history will be kind to me, since I intend to write it."
-
Winston Churchill