ABSTRACT
This chapter begins with the definitions of different types of electrical currents and current densities. It describes the current flow in metallic conductors, talks about different form of current distributions, and defines resistance, conductance, skin and proximity effects, ampacity, and Ohm’s law. It discusses isotropic and anisotropic conductors, continuity equations in integral and point forms, and the relaxation time. It classifies electrical materials as conducting, semiconducting, dielectric, or superconducting. It explores the properties of dielectric materials by using the classical approach involving polar and non-polar molecules, dielectric polarization, bound charge density electric susceptibility, and the relative dielectric constant. It thoroughly discusses boundary conditions to be satisfied by electric field at an interface between two differing materials. This begins with description of common configurations and the common forms of equations and describes the boundary conditions at the conductor-dielectric and dielectric-dielectric interfaces for E and D fields. An alternative approach to expressing these boundary conditions is also explored. It describes the capacitance in more detail. This includes its definition, evaluation, energy stored, types, and applications. It works out capacitance between two parallel plates, two cylindrical conductors of coaxial cable, two conducting spheres, and that of an isolated sphere.
