MQ135 adopts SnO2 as its gas sensitive material because SnO2 has low electrical conductivity in the clean air.So when surrounded by polluted air, the electrical conductivity of MQ135 will increase with the increase of pollutants, and the change in electrical conductivity can be converted to corresponding output signal. MQ135 has a high sensitivity to Ammonia, sulfide, benzene vapor, smoke and other harmful gas. It can detect various harmful gases, making it a cost-effective choice suitable for multiple applications.Target gas: Ammonia; methylbenzene; hydrogenProduct type: Semiconductor gas sensor Specification: Product model: MQ135Standard Package: Bakelite (Black Bakelite)Target gas: Ammonia; methylbenzene; hydrogenStandard circuit: Loop voltage Vc 24V DCHeater voltage: VH 5.0V0.2V AC or DCLoad resistance: Adjustable RLFeatures of sensitive components under standard test condition: Heating resistor RH 31&;3&; (room temperature)Heater power consumption: PH 900mWSurface resistance of sensitive material: Rs 2K&;-20K&;(in 100ppm NH3)Sensitivity: S Rs(in air)/Rs(100ppmNH3)5Concentration slope: 0.6(R100ppm/R50ppm NH3)Standard testing temperature/humidity : 202/65%5%RHStandard testing circuit: Vc:5.0V0.1VVH: 5.0V0.1VPreheating time: 48H Package Includes: 1x MQ135 Air Quality Sensor for