Abstract: A low breakdown voltage gas discharge device includes an envelope filled with an appropriately selected working substance. Two main electrodes are sealed in a vacuum-tight manner inside the envelope, and are separated by a predetermined distance. A supplemental electrode extends between the main electrodes along the direction of the electrical discharge, and has its geometrical and electrical parameters satisfy the following equation:S=I.sub.d /C,where S is the surface area of the supplemental electrode and depends on the distance between the main electrodes, I.sub.d is the current flowing in the supplemental electrode during normal glow discharge, and C is a constant characterizing the current I.sub.d, the composition of the supplemental electrode, and the type and pressure of the working substance. The supplemental electrode is connected to an AC or DC power source via a switch, so that the supplemental electrode always acts as a preparatory glow discharge cathode.