An Experiment on Impulse Excitation

There is described an oscillographic investigation of the current produced in an oscillatory circuit by a brief rectangular pulse of emf. directly introduced into the circuit. The pulse length is regulable. It is found that a pulse having a duration of one-half the natural period of the circuit produces the maximum disturbance. The bearing of the results on the effects of strays in reception is discussed. The behavior of "infinite impedance" loop circuits when subjected to pulse excitation is studied, and it is found that for pulses their filtering action is much reduced.