English: Graph showing the characteristic (current vs. voltage) curve of a glow discharge in neon gas at a pressure of 1 torr, between two planar electrodes separated by 50 cm. Original gave source of data as: C. F. Gallo, Coronas and Gas Discharges in Electrophotography: A Review, IEEE Transactions on Industry Applications, Vol.IA-13, No. 6, p.739 (1975)