Electric Circuits and Networks, Ist Edition by Pearson

part of the circuit that is being substituted and the remaining circuit except through the pair

of terminals at which they are interconnected.

Subject to the constraints on unique solution and interaction only through the

connecting terminals, we state the Substitution theorem as below (Fig. 5.3-8).

Let a circuit with unique solution be represented as interconnection of two networks

N

1

and N

2

and let the interaction between N

1

and N

2

be only through the two terminals at

which they are connected. N

1

and N

2

may be linear or non-linear. Let v(t) be the voltage that

appears at the terminals between N

1

and N

2

and let i(t) be the current flowing into N

2

from

N

1