THE SI-PLANAR-PELLISTOR ARRAY, A DETECTION UNIT FOR COMBUSTIBLE GASES

The detection of combustible gases with the aid of the heat exchange in chemical reactions on a solid surface has been known for many years. A large number of this type of sensor is used for gas detection. One of them is the Si-Planar-Pellistor, a small gas sensor, produced by Si micromachining technology. The advantage of this sensor is the low power consumption and the very low thermal time constant. A problem of all sensors using this method of heat exchange is the cross-sensitivity to most combustible gases. In this paper it will be shown how the cross-sensitivity can be reduced by using an integrated Si-Planar-Pellistor array or a single pellistor sensor operating at different working points as a quasi array in connection with signal evaluation by pattern recognition (PARC).