TABLE OF CONTENTS A pair of terminals at which a signal may enter or leave a network is called a port and a network having only one such pair of terminals is called a one-port network or simply a one-port. Similarly, a network having two ports, is known as a two-port network. When more than one pair of terminals is present, the network is known as a multi-port network.
A general network having two pair of terminals, one as the input terminal and the other as the output terminal, is a very important in various electrical and electronics systems. In such a network an electrical signal enters the input signal and leaves from the output terminals. Two ports containing no sources in their branches are called passive ports. If there is any source (voltage or current) in any branch they are called active ports.
A two-port network is shown in Figure 10.1(b). It has four variables (V 1, I 1, V 2, and I 2). The first two variables (V 1 and I 1) are input variables and (V 2 and I 2) are output variables. Only two of the four variables are independent and the other two are dependent. The dependence of two of the four variables on the other two is described in a number of ways depending on which of the variables are chosen to be the independent variables. There are six possible sets of equations between V 1,...
