A resistor for high-voltage measurements

A cheap and compact 100-megohm resistor for the measurement of direct or alternating voltages of power frequency may be constructed from thin-film resistance units similar to those commonly used as ¿grid leaks¿. The construction and performance of such a resistor are described. Errors due to corona or leakage along supports appear to be absent. There is a change of resistance with loading, due to the self-heating of the resistor. The magnitude of this change is approximately proportional to the square of the applied voltage and amounts to ¿2.6 per cent at 100 kV. By taking this change into account, voltages up to 100 kV may be measured correctly to 1 or 2 parts in 1000.