Sensitive material MQ-4 gas sensor is used to purify the air in the lower conductivity of tin dioxide (SnO2). when there are conditions in which the combustible gas sensor, the conductivity sensor with increasing concentration of combustible gases in the air increases. using a simple circuit to convert the change in the conductivity of the gas concentration corresponding to the output signal. MQ-4 is a high-sensitivity gas sensor for methane, propane, butane and has good sensitivity. this sensor can detect various combustible gases, especially natural gas, is the low cost of sensors for various applications.
After the sensor is working, it is necessary to warm up around 20s