MQ-136 GAS SENSOR (Hydrogen Sulphide Gas)

The MQ-136 is a Hydrogen Sulfide detection sensor with a sensing range of 1 – 200 ppm. The sensing element is SnO2, which has lower conductivity in clean air. When H₂S gas exists, the sensor’s conductivity gets higher along with the gas concentration rising. A simple circuit makes measuring this change in conductivity and turning it into data fairly straight-forward, but does require some calibration.