The article presents exemplary applications of devices with electric arc in gases of varying pressure used in industry practice and variants of the approximation of static arc characteristics. The article also contains an analysis of the influence of pressure changes on an arc damping factor function and presents mathematical arc models with a quasi-statically variable pressure parameter. The tests also involved simulations of processes in a simple circuit with an arc. The article also contains the results of calculations in the form of the evolution of dynamic voltage-current arc characteristics influenced by pressure changes.