TABLE OF CONTENTS The concept of a two-port was informally introduced in Chapter 5 to provide a common framework for the study of transformers and amplifiers. We now reexamine this concept from a more general and systematic viewpoint, using the network function concept developed in the previous chapter. We begin by introducing the two-port as a generalization of the one-port and find that there are six different ways of expressing its terminal characteristics, namely, via what are known as the z, y, a, b, h, and g parameter sets. We then illustrate the derivation of the four most common parameter sets, and we study two-port models, termination, and interconnections.
In the second part of the chapter we study an important two-port example, the magnetically coupled coil pair. Just as the two-port is a generalization of the one-port, the magnetically coupled pair is a generalization of the inductance, and a new concept emerges from this generalization, that of mutual inductance.
We conclude by demonstrating the use of SPICE to find two-port parameters as well as to investigate the transient and ac responses of magnetically coupled coils and transformers.
Before undertaking the study of two-ports, it is worth reviewing the concept of a one-port, as the former can be regarded as a generalization of the latter. Recall that a one-port, depicted in Figure 15.1(a), is a circuit with a pair of terminals, or port, through which signals and energy may enter or leave...
