ABSTRACT
The theorem applies to any linear active network (‘linear’ meaning that the measured values of circuit components are independent of the direction and magnitude of the current flowing in them, and ‘active’ meaning that it contains a source, or sources, of e.m.f.)
The above statement of The´venin’s theorem simply means that a complicated network with output terminals AB, as shown in Figure 33.1(a), can be replaced by a single voltage source E in series
Figure 33.1 The The´venin equivalent circuit
of the network at the terminals AB when all internal sources of e.m.f. are made zero. The polarity of voltage E is chosen so that the current flowing through an impedance connected between A and B will have the same direction as would result if the impedance had been connected between A and B of the original network. Figure 33.1(b) is known as the The´venin equivalent circuit, and was initially introduced in Section 13.4, page 174 for d.c. networks.
