Selective gas sensor for flammable (combustible, inflammable) gases

摘要

Selective gas sensors for flammable gases in air are made possible by the use of catalyst substrates of semiconducting BaTiO3-PTC ceramic. Compared with conventional gas sensors according to the pellistor principle, they are superior for two reasons: - The substantially higher temperature coefficients of the electrical resistance at the operating temperature of semiconducting BaTiO3 (100%/K) compared with platinum (0.2%/K) enable increased sensitivity to be achieved. - Owing to the constant self-regulating heating temperature, use of a plurality of PTC ceramics makes possible a selectivity in respect of various flammable gases having different commencement temperatures of the catalytic combustion.