The gas sensing material used in the MQ-7B carbon monoxide gas sensor is tin dioxide (SnO2), which has a low conductivity in clean air. The high and low temperature cycle detection method is used to detect carbon monoxide at low temperature (1.5V heating). The change in conductivity can be converted into an output signal corresponding to the gas concentration using a simple circuit.

The MQ-7B carbon monoxide gas sensor has high sensitivity to carbon monoxide. This sensor can detect a variety of carbon monoxide-containing gases and is a low-cost sensor suitable for a variety of applications.