Factors influencing the sparkover voltage of asymmetrically connected sphere gaps

THE sphere gap which is widely used as a method of measuring high voltage has its acceptance based on extensive calibration of the breakdown of air as a dielectric between spheres of specified sizes and spacings. The breakdown voltages between spheres of particular sizes are given for spacings up to a sphere diameter in the AIEE Standard no. 41 and in the British Standard no. 358.2