Semiconductor gas sensors are widely used due to high sensitivity to many chemicals and low costs, that make them interesting for applications in many different fields. In this paper a system for a complete evaluation of gas sensor response is described. An array of mass flow controllers and a radially symmetric stainless steel measurement chamber allowed to expose the sensors to controlled gas mixtures. The measurement chamber was designed to obtain an homogeneous flow without significant recirculating zones or stagnant volumes and to guarantee all sensors to be exposed at any time in the same conditions. A dedicated sensor holder avoided the need of microbonding procedures and allowed an easy mounting and a stable electrical contact with the sensor tracks and the platinum resistor embedded into the sensor support. The temperature of each sensor was independently controlled in the range 30 - 700 °C thanks to a PID control loop. The determination of the resistance-temperature calibration curves allowed to use the platinum resistors also as temperature sensors. The experimental set-up was fully automated by a dedicated software developed in Labview 7 environment. The gas sensors performance have been evaluated by this integrated experimental set-up in a fast, easy and complete way.
Experimental set-up for the evaluation of gas sensors performance
G Pioggia;
2008
Abstract
Semiconductor gas sensors are widely used due to high sensitivity to many chemicals and low costs, that make them interesting for applications in many different fields. In this paper a system for a complete evaluation of gas sensor response is described. An array of mass flow controllers and a radially symmetric stainless steel measurement chamber allowed to expose the sensors to controlled gas mixtures. The measurement chamber was designed to obtain an homogeneous flow without significant recirculating zones or stagnant volumes and to guarantee all sensors to be exposed at any time in the same conditions. A dedicated sensor holder avoided the need of microbonding procedures and allowed an easy mounting and a stable electrical contact with the sensor tracks and the platinum resistor embedded into the sensor support. The temperature of each sensor was independently controlled in the range 30 - 700 °C thanks to a PID control loop. The determination of the resistance-temperature calibration curves allowed to use the platinum resistors also as temperature sensors. The experimental set-up was fully automated by a dedicated software developed in Labview 7 environment. The gas sensors performance have been evaluated by this integrated experimental set-up in a fast, easy and complete way.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
