Franclim F. Ferreira, Pedro Guedes de Oliveira, Vítor G. Tavares

Two-port network

We call a two-port any four-terminal network in which the four terminals have been paired into ports. By port we mean a pair of terminals of a circuit in which, at all times, the instantaneous current flowing into one terminal is equal to the instantaneous current flowing out the other. For each port, we label one node the active node and the other one the reference node.

In a two-port network, each port is characterised by a voltage and a current, as in the following figure.

By convention, the voltage is measured from active to reference node and the current is considered to enter the active node.

This way, the terminal characterization of a two-port network can be made through the voltages and currents in both ports.