On the determination of resistance in terms of mutual inductance
Albert Campbell · Proceedings of the Royal Society of London Series A Containing Papers of a Mathematical and Physical Character · 1925
Abstract Some years ago the author made a determination of the ohm in absolute units by two alternating-current methods, both of which depended on calculated standard of mutual inductance and a measured frequency. Each of those methods had certain disadvantages: the first required a very steady running two-phase alternator, and the limits of accuracy depended on the readings of an electrostatic voltmeter; the second method employed condenser as intermediary and required an assumption regarding the behaviour of the condenser which was probably not quite justifiable. The following method requires simpler apparatus than the two former and is free from the difficulties inherent in them. The connections are shown in the figure.