Effective Date of Grant 1 1 January 1972

Low duty-cycle pulsed d.c. switching experiments have been performedon a variety of thin film Te-based semiconducting glasses. No premonitoryeffects are observed in the current-time profile of the non-switching OFFstate. If, however, the threshold voltage is exceeded, a continuouscurrent increase with time throughout the normal delay-time regime(pre-switching OFF state) is always observed prior to switching. In agiven device or film this current rise is interrupted, independent of over-voltage, by the rapid switching transition at about the same relativecurrent increment above the current background extrapolated to zero-time(leakage current). In the switched or ON (filamentary conduction) statethe current level, as limited by the series.load resistor, can determinethe response of the device in the subsequent pre-switching OFF state.For loads in excess of ~ IkO, there is no effect on the pre-switching OFFstate characteristics. For appreciably smaller loads, there is a continuousincrease in delay time with increased pulse length (time spent -in theprevious ON state).