Methods of Analysis

The circuits and networks examined in the previous chapters permitted the combination of series and parallel elements in the search for specific unknowns. Situations will arise, however, where sources, elements, or branches are not in series or parallel and such reduction techniques cannot be applied. The result is the need to develop an approach using the basic laws of electric circuits that will work for any configuration. The approach chosen is determined by whether our primary interest is in the currents of the network or the voltages from a specific point to ground. The methods of analysis introduced in this chapter include branch-current analysis and mesh analysis if the currents are desired and nodal analysis if the voltages are to be found. All three methods can be applied to any network with any number of sources although the desired unknowns will determine which is applied. It will take a measure of effort to apply each method for the first time. However, in time, with practice, you will find that each method can be applied very quickly and accurately without an enormous concern about errors creeping in the process. In fact, you will almost be amazed as to how powerful the methods of analysis can be. They can solve the most complex network with any combination of elements in any arrangement in very short order. Before examining one of the methods, the concept of a current source must first be introduced. In previous chapters only voltage sources such as a battery or supply were encountered. The current source is very common in the analysis of electronic circuits because it appears in the models (network equivalent) of some of the most common electronic devices such as the transistor. There are commercially available current sources, but in actuality they are voltage sources that have been designed to act as current sources for a specific application. Want to know current sources, lets go!