Reg, G4FGQ wrote:
"A complicated circuit is reduceable to an equivalent circuit consisting
merely of two components: a current source and an impedance."? "Let`s
hope his name will be pronounceable."

True. Does the name "Norton", as in Norton`s Theorem, seem
pronounceable? Reg`s assertion is indubitable.

In a linear circuit, any generator of electric power may be considered
equivalent, at specified frequency, to a current generator whose current
is equal to the short-circuit current in shunt with an admittance whose
magnitude is equal to that when the generator is inactive and there is
no load connected to it, says Henney in his "Radio Engineering
Handbook".

The Thevenin`s Theorem impedance is the open-circuit voltage divided by
the short-circuit current.

Terman says on page 95 of his 1937 2nd edition of "Radio Engineering":

"According to Thevenin`s theorem, any linear network containing one or
more sources of voltage and having two terminals behaves, insofar as a
load impedance connected across the terminals is concerned, as though
the network and its generators were equivalent to a simple generator
having an internal impedance Z and a generator voltage E, where E is the
voltage that appears when no load is connected and Z is the impedance
that is measured between the terminals when all sources of voltage in
the network are short-circuited."

We have argued about the linearity required to make the Thevenin
equivalent valid. Terman says that linearity is the only limitation to
validity.

Best regards, Richard Harrison, KB5WZI