CSZ Pt, O2 galvanic cells (g.c.) based on calcium-stabi-lized ZrO2 anodic films of cubic modification (CSZ) are studied at 450–700 K in various gas media. The CSZ
anodic films are synthesized by microspark oxidation in solutions of a calcium salt. The role and effect of
chemisorption, catalytic, and diffusion processes on the g.c. emf are revealed. The nature of the electronic com-
ponent of conductance in the CSZ anodic films, which is caused by an extremely low oxygen pressure at the
zirconium electrode equal to the pressure of the CSZ decomposition, is determined. An effect of the electronic
component on the g.c. emf is estimated. Variations in the emf, conductivity, and response of the g.c. with tem-
perature and concentration of oxidizing gases are determined experimentally and theoretically. A general equa-
tion describing the dependence of the g.c. emf on the temperature and concentration of a gaseous reagent is
derived. The study provides a basis for the development of a novel, highly sensitive potentiometric sensor for
measuring concentrations of fuel and toxic gases in air.