MQ3 gas sensor module is highly useful for gas leakage detection at home or industry. The sensor module can detect Alcohol, Benzine, CH4, Hexane, LPG, CO. It is highly sensitive and responding time is very fast. Depending on the requirements of sensitivity, the sensor can be adjusted with a Potentiometer.MQ3 is both digital and analog outputs sensor which is commonly used to detect the presence of alcohol gases. It is a low cost semiconductor type Gas Sensor. It can detect the presence of alcohol gases at concentrations from 0.05 mg/L to 10 mg/L. The output voltage of the gas sensor increases if the concentration of gas increases. The sensitivity of the sensor is adjustable by the Potentiometer.