Electromagnetic Field Theory

4

Metals, Dielectrics, Resistors, Capacitors, Inductors, Conductors and Magnetic Materials

4.1 INTRODUCTION

Materials are described in terms of conductivity (σ). Conductivity depends on temperature and frequency. A material with high conductivity (σ >>1) is called a “metal.” A material with low conductivity (σ <<1) is called an “insulator.” For semiconductor materials, the conductivity lies between the conductivity of metals and insulators.

4.2 CONDUCTOR OR METALS

A conductor contains moving free charges. An isolated conductor is shown in Figure 4.1. Let an external electric field E be applied on it. A force will get applied on the charges inside the conductor. As a result, charges will get accumulated on the surface. These induced charges generate ...