with the system and, in the case of transformers,
how a voltage applied between
two terminals is transferred to other terminals.
A terminal model can be represented
by a circuit which interconnects the different
terminals of the component being modelled.
Such a model has as many nodes as
terminals, plus one to represent ground.
The equations of a circuit with n nodes can be
expressed in the frequency domain in terms of its
admittance matrix as follows: