The MQ5 is used in gas leakage detecting equipments in consumer and industrial applications, this sensor is suitable for detecting LPG, natural gas and coal gas. The sensitivity can be adjusted by using the potentiometer. MQ-5 gas sensor has high sensitity to Methane, Propane and Butane, and could be used to detect both Methane and Propane. The sensor could be used to detect different combustible gas especially Methane, it is with low cost and suitable for different application. MQ-5 gas sensor is SnO2, which with lower conductivity in clean air. When the target combustible gas exist, The sensors conductivity is more higher along with the gas concentration rising. Please use simple electrocircuit, convert change of conductivity to correspond output signal of gas concentration.