Abstract :
The design of moving-coil instruments includes a consideration of such factors as damping and speed of response, in addition to torque, resistance, etc. Some information has been published on this subject, but it is rather scattered; this paper is an attempt to present the information necessary to understand the performance of a moving-coil instrument under various conditions in as complete a form as possible, and in such a form that it can readily be used. In the ordinary forms of instruments such as ammeters and voltmeters, the time/deflection characteristics are of importance in determining the damping and the time of response, but have no effect on the steady reading of the instrument. In special types of instrument, such as the ballistic galvanometer and the flux meter, the time/deflection characteristics are of importance in determining the reading given by the instrument.
