Читать книгу Introduction To Modern Planar Transmission Lines - Anand K. Verma - Страница 143

The electric and magnetic fields are visualized through the line of flux. Thus, the electric charge (Q_e) is described by the electric flux (Ψ_e). The total charge (Q_T) on a physical body and the corresponding electric flux are related by Gauss’s law:

(4.1)

If the charge is distributed throughout the volume of a body, in the form of volume charge density ρ_e, the elemental charge in the volume element dv is ρ_edv. The flux is further expressed as the electric flux density (D), i.e. the flux per unit area. The flux through the elemental surface area is It is shown in Fig. (4.1). The flux density is a vector quantity. It is also called the electric displacement vector.