A comparative study of the DC and AC model for thin film sensors for the detection of gases

When a gas is passed over a thin film sensor, its electrical properties like resistance/conductance, capacitance change due to diffusion of the gas. These changes can be studied by simulating the sensor response on giving a step change in the gas concentration. It is sometimes difficult to select an appropriate model for simulating the sensor response. This paper presents simulation of two models viz. the DC model or the Device Conductance Model and the AC model for three input gases, Methanol, Acetone and Ethyl Acetate. For the same step input, the percentage change in response for both models for change in conductance is observed. The DC model exhibits a higher percentage change in conductance than the AC model.