Steve Nosko wrote:
"I disagree." (If part of the source resistance were not lossless
efficiencies would be limited to 50%.)

Before I sent that I asked myself if it were necessary to include the
peoviso that the statement only applies to maximum power transfer. Sez
to myself, no don`t bother. Any schoolboy knows that when the load
resistance is large as compared with the source resistance, you may
exceed 50% efficiency. That`s the norm for power distribution. Also, sez
to myself, the title of the thread is:
" max power transfer theorem"

Surely it`s understood the comments refer to maximum power transfer and
not to a less demanding condition.

Me, myself, and I were wrong.

Best regards, Richard Harrison, KB5WZI