The gas sensitive material used in MQ-8 gas sensor is SnO2, which is of lower electrical conductivity in clean air. When there is hydrogen in the environment where sensor resides, the electrical conductivity of the sensor increases with the increase of the hydrogen concentration in the air. The change of electrical conductivity can be converted to the output signal corresponding to that of the gas concentration by using a simple circuit. The sensitivity of MQ-8 gas sensor to hydrogen is quite high, it can also detects a variety of other gases containing hydrogen. This sensor, which is suitable for a variety of applications, is definitely a good catch.