Pulsed mode of operation and artificial neural network evaluation for improving the CO selectivity of SnO2 gas sensors

Stannic oxide sensors were developed to monitor CO concentrations (10-200 ppm). Cross sensitivities of these sensors against humidity (20-80% r.h.) and methane (400-2000 ppm) can be suppressed by evaluating "mode of operation" data. For this purpose, a sequence of switched operation temperatures introduces kinetic parameters. The latter are evaluated by model-based, or data-based algorithms. For this approach to achieve high selectivity, micromachined sensor dies are particular suitable as they show low thermal inertia. (C) 2000 Elsevier Science S.A. All rights reserved.