Output Characteristics of a Gas-Polarographic Oxygen Sensor Using a Zirconia Electrolyte in the Knudsen Diffusion Region

Output characteristics of a gas-polarographic oxygen sensor using a zirconia electrolyte have been investigated at 450°C and low pressures (∼1 mmHg) in O 2 -N 2 gas mixtures with the aim of clarifying those in the Knudsen diffusion region. The limiting current obtained at 1 mmHg of the total pressure increased linearly with the oxygen concentration up to 100% in the ambient atmosphere as expected from the theoretical consideration on the output characteristics of the sensor in the Knudsen diffusion region.