Measurement of very short time lags

THE time lag of electrical breakdown of various air gaps and solid insulations is of particular importance in co-ordination¹ of insulation for transient lightning surges. Generally, time lag of breakdown is in part a function of chance ionization conditions in the breakdown path and therefore the measurements become often of a statistical nature.² Thus, where a large number of measurements are to be made, a direct method giving immediate readings free from the delays of photographic development would be a valuable auxiliary to cathode-ray oscillography.