The method described has been used to obtain, in a spark-gap, current pulses of up to 500 amp in amplitude and 10 microsec in duration with a fall-time of less than 0.25 microsec. The discharge in anRCcircuit is modified by inductanceto maintain the current in the gap approximately constant for a period of up to about one-half of the unmodified time-constant; the current in the gap is then chopped by a triggered spark-gap, through which the discharge is completed. Non-linear resistance is used to reduce the fall-time to between onehalf and one-third of that obtained with linear resistance.