Is Current the Conduction of Charge?

Abstract

Most scientists believe that current flow is the conduction of charge. Mathematics and physics imply otherwise. The mathematics of magnetism requires another component, the displacement current that depends on the time derivative of the electric field. Displacement current is an experimental reality. Displacement current is needed for light to propagate in a vacuum devoid of charges. Maxwell himself defined true current to include displacement current. Mathematics and Maxwell both show that displacement current is an essential part of electrodynamics. The success of circuits as the main application of electricity from telegraphs to computers depends on the special properties of displacement current. Those properties allow current flow to be analyzed by Kirchhoff's law (generalized) without dealing with properties of individual charges. Hundreds of equations are needed to specify currents with Kirchhoff law for currents instead of astronomical numbers needed to specify charges with the continuity equation.