Template: MQ-135 Gas Sensor Spec

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The gas sensing material used in the MQ135 gas sensor is tin dioxide (SnO2), which has low conductivity in clean air. When there is polluted gas in the environment where the sensor is located, the conductivity of the sensor increases with the increase of the concentration of polluted gas in the air. The MQ135 gas sensor has a high sensitivity to ammonia, sulfide, and benzene-based vapors, and is ideal for monitoring smoke and other harmful gases. This sensor can detect a variety of harmful gases and is a low-cost sensor suitable for a variety of applications.


  • Sensitive for benzene, alcohol, smoke
  • Output voltage boosts along with the concentration of the measured gases increases
  • Fast response and recovery
  • Adjustable sensitivity
  • Signal output indicator


  • Power: 2.5V ~ 5.0V
  • Dimension: 40.0mm * 21.0mm
  • Mounting holes size: 2.0mm
  • Sensitive gases: ammonia, nitrogen oxides, alcohols, aromatic compounds, sulfides, fumes


PIN Description
DOUT Digital data output
AOUT Analog data output
GND Ground
VCC Power input (2.5V~5.0V)