Si-planar-pellistor: Designs for temperature modulated operation

Drift problems often cause complications in practical applications. Modulation techniques which improve the performance of sensor systems are normally limited to very low frequencies because most sensors have a very slow response. The Si-planar-pellistor which is a miniaturised sensor applying the catalytic principle makes a modulation of temperature at frequencies up to 100 Hz possible. The optimisation of the sensor for modulated operation is the main topic of this paper. Thanks to miniaturisation power consumption is as low as 40-80 mW. Measurements show that the use of modulated mode improves the long-term stability and makes a reliable identification of combustible gases possible.