Sensitive material MQ135 gas sensor is used in clean air low conductivity tin oxide (SnO2). When the sensor is kept in their environment In the polluting gases , the conductivity sensor with increasing air pollution in gas concentration increases. Using a simple circuit can change the conductivity Conversion of an output signal corresponding to the gas concentration . MQ135 sensor for ammonia, sulfide , benzene vapor high sensitivity of the smoke and other harmful monitor is also very good. This sensor can be seized Measure a variety of harmful gases , is a low-cost sensors for a variety of applications .