MST133 gas-sensitive material used by the gas sensor is tin dioxide (SnO2), which has a low conductivity in clean air. When the sensor encounters the detected gas, the resistance of the sensor changes, and the conductivity of the sensor increases correspondingly with the increase of the detected gas concentration. According to this characteristic, a simple test circuit can be designed to convert the change of conductivity into a signal output corresponding to the change of gas concentration, so as to realize the detection of gas.

MST133