This paper describes a method for determining the dynamic current voltage characteristic curves of glow discharge tubes. The technique differs from that previously used for the oscillographic study of glow tubes in that the manner in which the current varies with time is under control. This is accomplished by the use of a vacuum tube to limit the current passed by the glow tube. The rate at which the current rises and falls, the current amplitude, the frequency of repetition of the current cycle, and the interval between cycles can be varied at will by changing the wave form of the voltage applied to the grid of the control tube, and the grid bias of the control tube. A number of oscillograms obtained by this method are shown, and the form of the characteristics is explained on the basis of time taken for ionization and deionization of the gas.