Effect of temperature changes on the maintaining voltage of a normal glow discharge

Abstract

Previously published methods of estimating the change in maintaining voltage Vm of a normal glow discharge (in which an anode fall is not present) caused by a change in the envelope temperature Tw are discussed. As cylindrical tube geometry was used in each case, exact solutions were not obtained. This paper considers a spherical cathode centrally situated in a spherical envelope for which arrangement an exact solution is possible. Predicted results agree with experimental measurements. Using a simplified model of a glow discharge tube the theory is extended to include the case in which an anode fall is present. Qualitative results show that dVm/dTw, the temperature coefficient, can change from negative to positive under certain conditions due to commencement of formation of an anode fall. This conclusion is confirmed by measurement of the coefficient for an adjustable-gap tube operated in the normal glow discharge region.