ABSTRACT
Any circuit that is excited by a single, independent source applied to one port, and having a load connected to another port, can be considered as a two-port circuit. A two-port circuit is characterized, in general, by sets of four parameters defined in terms of open-circuit or short-circuit terminations at each port. Terminal voltages and currents of two-port circuits are usually considered to be in the s domain, that is, as Laplace transforms of the corresponding functions in the time domain. The derivation of the composite parameters when two-port circuits are connected in cascade, in parallel, in series, in series-parallel, or in parallel-series, and application to some special cases of interest. The simple two-port circuits may be combined in one of five types of connection: cascade, parallel, series, series-parallel, or parallel-series. Two other connections of two-port circuits are possible, series-parallel and parallel-series.
