The gas-sensing material used in the MQ-4B gas sensor is tin oxide (SnO2) with a low conductivity in clean air. When there is a combustible gas in the environment in which the sensor is present, the conductivity of the sensor increases as the concentration of combustible gas in the air increases. The change in conductivity can be converted to an output signal corresponding to the gas concentration using a simple circuit. MQ-4B gas sensor on the high sensitivity of methane, alcohol and other interfering gases have a strong anti-interference ability.
Good sensitivity to methane over a wide range of concentrations
With long life
Drive circuit is simple and so on
Widely used in household gas leak alarm, industrial combustible gas alarm and portable gas detector.