ABSTRACT
At the end of this chapter you should be able to:
• understand and use Thévenin’s theorem to analyse a.c. and d.c. networks
• understand and use Norton’s theorem to analyse a.c. and d.c. networks
• appreciate and use the equivalence of Thévenin and Norton networks
Many of the networks 35 using Kirchhoff’s analysis and the more quickly and easily theorems. Each of these
what may be a complicated network of sources and linear impedances with a simple equivalent circuit. A set procedure may be followed when using each theorem, the procedures themselves requiring a knowledge of basic circuit theory. (It may be worth checking some general d.c. circuit theory in Section 15.4. page 226, before proceeding.)
Thévenin’s∗ theorem states:
‘The current which flows in any branch of a network is the same as that which would flow in the branch if it were connected across a source of electrical energy, the e.m.f. of which is equal to the potential difference which would appear across the branch if it were open-circuited, and the internal impedance of which is equal to the impedance which appears across the open-circuited branch terminals when all sources are replaced by their internal impedances.’
