Sensor Used in E-nose - The Electronic Nose Artificial Olfaction Technology - page 153

Fig. 6.8 a Pellistor sensor, b odor sensor used in wheatstone bridge

(a) Chemiresistive

The working principle of this material is that a change in property of the
material resulting from interaction with a gas/odor leads to a change in resistance
in the sensor. For each material type, the mechanisms that lead to resistance
changes are different. Conducting polymer (CP), intrinsically CP and metal oxides
(MOS) are three of the most commonly utilized classes of sensing materials.
Figure 6.9 shows the MOS type chemiresistive sensor used in E-nose system.

Fig. 6.9 Chemiresistive sensor