
Principles of Analog Electronics
206
To guarantee the equivalence, the voltage v must be unchanged across the
e
lements and the owing currents
i
and
i
2
, so
viiZ Zi Zi
=+
12
hence the assertion.
6.8 SUBSTITUTION THEOREM
The substitution theorem states that “for branch equivalence, the terminal volt-
age and current must be the same.” According to the theorem, the components
in a network can be interchanged, so long as the terminal current and voltage are
maintained.
This theorem can be considered a generalization of the Thévenin or Norton
statements.
With the substitution theorem we can, for instance, realize a source conversion
(which is someti ...