walt wrote:

But Roy, consider that the source resistance remains constant at 10
ohms. Then what load resistance will absorb the most power? The answer
is 10 ohms. Any value of load resistance greater or less than 10 ohms
will result in less power delivered. I don't believe it's fair to
change the source resistance when dealing with the Maximum Power
Transfer Theorem.

In your example with a source resistance of 10 ohms and a load
resistance of 50 ohms the power delivered will be 1.39 watts. But when
the load resistance is 10 ohms with the same source resistance the
power delivered is 2.5 watts. As I said above, if the load resistance
is either greater or less than 10 ohms the power delivered will be
less than 2.5 watts. Thus when the source resistance is constant the
maximum power will be delivered when the load is matched to the
source.

Nes pa?

Walt

Of course, I know that, and I would hope anyone with even very basic
electrical circuit analysis knowledge does. And anyone with that
knowledge should state as you have,

"FOR A GIVEN SOURCE IMPEDANCE, maximum power transfer occurs when the
source and load impedances are matched (i.e., the load impedance is the
complex conjugate of the source impedance)," which is true.

But the statement which was made was that "Maximum power transfer occurs
when the source and load impedances are matched." This is NOT true, as
the example demonstrates.

It's an important distinction. Instead of declaring what's "fair" and
what isn't with regard to changing source and load impedances, the
maximum power transfer theorem should be stated correctly, in a way
which makes it true.

Roy Lewallen, W7EL