Experimental Investigations on the Impedance Characteristics of the Gas Sensors

For commonly-used gas sensors, their resistance characteristics are mostly exploited for gas detection and identification. However, in practical, the gas sensors exhibit complicated impedance characteristics which probably include resistive, capacitive and inductive response during the inter-reaction between the gas molecules and the sensing materials. We designed and built a dedicated measurement system based on the frequency scanning method for the research of the impedance characteristics of the gas sensors. 11 types of commercial gas sensors were chosen, and their impedance characteristics in response to the ethanol and the acetone were measured separately. We analyzed the frequency response, the concentration response and the corresponding trends according the measurement results.