An attracted-disc absolute voltmeter

Details are given of the design and performance of an attracted-disc voltmeter, operating in a medium of compressed gas, which is capable of measuring the effective value of a wide range of voltages. The accuracy with which measurements can be made increases with the magnitude of the voltage and is about 1% at 1 kV and 0.1% at 30 kV and above. The clearances between the electrodes have been designed to withstand voltages up to 700 kV (peak), but measurements have been limited to 350 kV (peak) by the insulator used to support the high-voltage electrode.