Capacitance and Related Effects

Aspects of energy storage and conversion in simple mechanical and electrical systems were discussed in Chapter 1. Mechanical systems generally have compliance, inertia, and friction. The counterparts of these in electrical systems are capacitance, inductance, and resistance, and are shown in Table 1-1. The energy associated with capacitance and inductance in electrical circuits where the capacitance and inductance are constant is reversible because the energy absorbed in a constant capacitance or in a constant inductance can be recaptured completely in electrical form. However, the energy absorbed by a resistance is irreversible because it is converted into heat and therefore cannot be recaptured in electrical form without the intervention of some external agency. It is with capacitance and related effects that this chapter is concerned. Since field theory forms the basis upon which the concept of capacitance rests, a brief review of some of the principles pertaining to electric fields may be helpful to the student.