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1995
Journal Article
Titel
A test system for gas sensors
Abstract
An important instrument for development of gas sensors is the test and measurement system. Whereas for calibration of commercial gas sensors prefabricated gas mixtures were often used, for research purposes a more flexible system is needed. The test system of IFT (Fraunhofer-Institute Solid State Technology) provides independent mixing of two test gases together with a humidification at a high dynamic range. The gas mixture is performed via a volumetric method. Two test chambers were developed, optimized for a small volume and a well defined gasstream. These test chambers contain simultaniously up to 1 0 sensors of different types (semiconductor, dielectric, QMB, SAW ... ) and provide measurement of gas temperature and pressure. The exhaust gases are analysed via a dew point mirror and an optional infrared gas analyser. The article describes the main installation plan, the most important formulas for volumetric mixing systems and humidification and gives an example of a sensor measurem ent.