Chapter 6 - Capacitance

Abstract

This chapter discusses capacitance, which is a measure of the capacity of conducting bodies to store charge. Capacitance is increased if a polarizable material fills the region between the two capacitor plates. This decreases the magnitude of the electric field within the material by a factor called the dielectric constant. The combination of geometry and dielectric constant is responsible for the large capacitance of the Leyden jar and of the recently developed electrolytic capacitors. The potential of a capacitor can be determined by summing up the potential due to all its charges, thought of as point charges. The chapter reviews the two-plate capacitors, parallel-plate capacitors, concentric spherical two-plate capacitor, and concentric cylindrical two-plate capacitor. A major advance in capacitor design was the introduction of electrolytic capacitors, which have a very thin layer of dielectric separating the two plates of the capacitor.