The striking and breaking potentials for electron discharges in hydrogen

Abstract

1. It is well known that in thermionic tubes containing gas at a low pressure discontinuous increments of the current occur at certain critical voltages. They are usually accompanied by the appearance or disappearance of luminosity or by change of type of some luminosity already present. The phenomena are irreversible, the “striking” potential at which a given type of discharge sets in being usually higher than the “breaking” potential at which the same type of discharge reverts. These effects are in general very complicated and depend on the geometrical structure and arrangement of the electrodes, the nature and pressure of the gas, and the temperature of the emitting cathode. They also seem to depend on the previous history of the tube and generally to behave in a capricious manner. The following experiments, which are confined to hydrogen as the gas, show that under the conditions described the phenomena are quite definite and reproducible and not too complicated.