SI-PLANAR-PELLISTOR - DESIGNS FOR TEMPERATURE MODULATED OPERATION

Drift problems often cause complications in practical applications. Mo dulation techniques which improve the performance of sensor systems ar e normally limited to very low frequencies because most sensors have a very slow response. The Si-planar-pellistor which is a miniaturised s ensor applying the catalytic principle makes a modulation of temperatu re at frequencies up to 100 Hz possible. The optimisation of the senso r for modulated operation is the main topic of this paper. Thanks to m iniaturisation power consumption is as low as 40-80 mW. Measurements s how that the use of modulated mode improves the long-term stability an d makes a reliable identification of combustible gases possible.