Spark Lag of the Sphere Gap

Measurements of time lag of spark-over of small sphere gaps at 3,820 volts were made with an instrument developed specifically for the purpose. Spark lags were found to fall into 3 distinct domains: 1 of relatively long initiatory lags of random distribution, and 2 of definite formative lags of different orders of magnitude corresponding to 2 different spark-over mechanisms. The controlling conditions which determine into which domain the spark lag will fall are given. The manner in which this lag may obscure the sparking voltage of the gap is pointed out and a remedial specification suggested. The results are applicable to larger sphere gaps and higher voltages.