The use of the Grassot fluxmeter as a quantity meter: its application to the determination of the moment of intertia of a small direct-current armature

The question of the measurement of the quantity of electricty passed through a circuit in a given time is intimately connected with the magnitude of this time of passage. The paper describes the use of a Grassot fluxmeter for such measurements and gives the theory of the instrument when so used. It is shown that this instrument provides a useful intermediary when the time of passage is such that neither the ballistic galvanometer nor the ampere-hour meter can be used successfully. The determination of the moment of inertia of a small d.c. armature, using a fluxmeter, is described, and the results obtained are verified by two alternative methods of determination.