PRECISE MEASUREMENT OF SHORT TIME INTERVALS BY USE OF THE MICROCHRONOGRAPHIC WHEEL
George R. Town · Review of Scientific Instruments · 1930
Apparatus and methods are described by which time intervals may be measured to a precision of twenty microseconds. The duration of the time interval may be anything between twenty microseconds and ten seconds or even longer. The record obtained is continuous, making it possible to locate any event within the time interval to this same precision. The method is not limited to the measurement of electrical quantities. The application of the method to the determination of the speed of a rotating shaft is given in detail.