The a.c. properties of resistors and potential dividers at power and audio frequencies, and their measurement

Abstract

The alternating-current properties of resistors are briefly discussed, and the time constant and equivalent series inductance and shunt capacitance are defined. The reasons for the variations with frequency are outlined. The determination of the properties is based on standard resistors with windings of simple geometry, for which the inductance and capacitance are calculable. The paper describes methods for comparing such standards with ordinary resistors, for values ranging from a small fraction of an ohm up to about a megohm; particular attention is given to potential dividers of the Kelvin-Varley type, which have great utility in these measurements. The choice of method depends upon the value of the resistor and, for low values (less than, say, 10 Ω), whether the resistor is a two- or four-terminal one.