Keith Dysart wrote:
Anyway, examples of what you are looking for exist
in most amplifiers. They are often called blocking
capacitors. They charge to the DC voltage but pass
the signal. They are not particularly good voltage
sources, but that is their role in the circuit, and
they do it admirably well.

Sorry, no modifications allowed. I simply want you
to prove that the voltage source impedance minus
the series resistor is zero ohms as you say.
--
73, Cecil http://www.w5dxp.com