An absolute electrometer for the measurement of high alternating voltages

Abstract

An absolute electrometer of the attracted-disk type is described . It is suitable for the measurement of alternating voltages up to 275,000 volts effective value with an accuracy of a few hundredths of a percent. A set of equally spaced coaxial guard hoops, maintained at equally spaced potentials, serves to produce a uniform field at the disk in spite of the large separation (110 cm) required to avoid sparkover at the high operating voltage. Formulas are derived by which corrections can be applied for any deviation of the individually measured hoop potentials from the ideal equal spacing.