Measurement of Transients by the Lichtenberg Figures

The paper gives the results of a comprehensive study of the effect of transients on the size and appearance of Lichten berg figures. Sixteen different rates of voltage rise were used, varying from about 20 minutes to 0.1 microsecond to reach a crest value of 25 kv. Results were obtained with transients the crest voltages of which ranged from 5 to 25 kv. The steeper wave fronts were checked with the Dufour cathode-ray oscillograph. Calibration curves are given, showing that the positive figures are not much affected by changes in wave front, while the negative figures vary considerably with changes in wave front, especially at the lower voltages. The positive figures are divided into three types according to their appearance which is found to depend on the rate of voltage rise. It is concluded that for most conditions the size of the positive figures will give a determination of the crest voltage of the applied transient to within approximately 25 per cent.