Surge impedance

In the conventional treatment of traveling waves on lossless lines, inductance and capacitance per unit length of line are used. Such treatment results in the usual concept of surge impedance and only certain aspects propagate with the velocity of light. The usual concepts of inductance and capacitance are defined in terms of their steady-state values. In the present paper, the treatment follows from electric field concepts in which the propagational time delays are taken into consideration through the use of retarded potentials. The current that flows is determined when a unit EMF is suddenly inserted in series in an infinitely long isolated conductor of zero resistance. The current equals the transient surge admittance and its reciprocal is the transient surge impedance. The surge impedance increases with time in a determinable manner from a very small value. When such a conductor forms only the connecting leads to a pair of infinitely long parallel conductors, the surge impedance approaches the conventional value for the parallel lines.