ABSTRACT
This chapter discusses terminal and port representations of circuits. Particular attention is given to the distinction between terminals and ports. Applications show the usefulness of terminal and port representations. Subcircuits are connected to other subcircuits using terminals or ports. Terminal and port representations of a subcircuit describe how that subcircuit will act when connected to other subcircuits. The terminal voltages were selected to be the independent variables and the entries in the matrix are admittances. A port consists of two terminals with the restriction that the terminal currents have the same magnitude but opposite sign. The use of ports assumes that the currents in the terminals comprising a port are equal in magnitude and opposite in sign. Port and terminal parameters describe how the subcircuits interact with other subcircuits but do not describe the inner workings of the subcircuit itself.
