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Distributed Circuit theory

The first of these is known as distributed Circuit theory (which is one step up from lumped

Circuit theory) and resembles lumped Circuit theory to some degree. This level of theoryis applicable when we still have

•    an idea of where the currents are, either on thin wires or spread uniformly over either the cross section or the surfacc of a wire of finite size, and

•    some idea of the shape of the magnetic field distribution and that there are planes

in which although the magnetic field varies from point to point within the piane, the

magnetic field is everywhere parallel to that piane.

When this last condition is satisfied we havc a situation where the linę intcgral of the clcctric field between two points in that piane is independent of the path (provided the

path is confined to that piane) and we can still usefully speak of the potential difference

between two points in the piane.

In distributed circuit theory current and potential conccpts may still be used subject to the limitations just recogniscd. We will apply this methodology cxtensively in our study of transmission lines in Chaptcrs 2 and 3.