Modeling and validation of the transient response of a temperature modulated gas sensor to ethanol

In this paper, a commercial metal-oxide gas sensor was first placed under temperature modulation regime and simultaneously their transient response to various concentrations of ethanol vapors was recorded. By applying the temperature modulation, the sensor surface temperature was also recorded by a S-type thermocouple. Then, the performance of these sensors was expressed based on the both air oxygen absorption model and ethanol absorption on the surface of the sensitive layer using the Freundlich isotherm equation. Further, this model is simulated using the MATLAB software in the simulink environment. Using this model, one can see the sensor's dynamic response to ethanol. In this model, the concentration of a gas is considered as a voltage. This parameter, along with the temperature profile of the sensor surface under temperature modulation and sensor conductance under the influence of air oxygen, are considered as inputs of the model and transient response of the sensor as output of the model. The parameters of this model are calculated based on the approximate criterion of simulated responses and the responses recorded for each concentration of ethanol gas. The simulation results based on the average simulated parameters also showed that the simulated responses were close to the actual recorded responses.