The measurement of high voltages with indicating or recording instruments

The paper reviews the methods by which the mean, r.m.s., or peak values of voltages ranging from 10 kV upwards may be measured by indicating or recording instruments to an accuracy within about 1%. Most of the methods use either a low-range high-impedance voltmeter or cathode-ray oscillograph in conjunction with a voltage divider or a milliammeter in series with a high impedance. Voltage dividers suitable for use with direct, alternating and impulse voltages are considered, and, amongst the measuring instruments, the diode peak voltmeter is discussed in some detail. High-range electrostatic voltmeters are also considered. It is concluded that there are always at least two different methods by which a particular type of voltage may be measured.