An accurate adjustable contact breaker
J L Parkinson · Journal of Scientific Instruments · 1926
A revolving contact breaker is described which is capable of providing intervals (e.g. that of the passage of a constant current or that between two induction shocks) from 0.001 to 9 seconds. The driving power is derived from a gramophone motor, the speed of which from one winding is constant over about 100 revolutions, and is attained within one-eighth of a revolution starting from rest. Such an instrument was originally designed by the late Dr Keith Lucas, F.R.S., but has never been described. In a slightly modified form it has been found to be of the greatest use in physiological and other experiments.