1.2 THE LUMPED CIRCUIT ABSTRACTION
Consider the familiar lightbulb. When it is connected by a pair of cables to
a battery, as shown in Figure 1.4a, it lights up. Suppose we are interested in
finding out the amount of current flowing through the bulb. We might go about
this by employing Maxwell’s equations and deriving the amount of current by a careful analysis of the physical properties of the bulb, the battery, and the
cables. This is a horrendously complicated process.