Transcription of TECHNICAL DATA MQ-135 GAS SENSOR - Olimex
1 TECHNICAL DATA MQ-135 GAS SENSOR FEATURES Wide detecting scope Fast response and High sensitivity Stable and long life Simple drive circuit APPLICATION They are used in air quality control equipments for buildings/offices, are suitable for detecting of NH3,NOx, alcohol, Benzene, smoke,CO2 ,etc. SPECIFICATIONS A. Standard work conditionSymbolParameter nameTechnical conditionRemarks VcCircuit voltage5V OR DC VHHeating voltage5V DC RLLoad resistancecan adjust RHHeater resistance33 5%Room Tem PHHeating consumptionless than 800mw B. Environment conditionSymbolParameter nameTechnical conditionRemarks TaoUsing Tem-10 -45 TasStorage Tem-20 -70 RHRelated humidityless than 95%Rh O2 Oxygen concentration21%(standard condition)Oxygenconcentration can affect sensitivityminimum value isover 2% C. Sensitivity characteristicSymbolParameter name TECHNICAL parameterRamark 2 RsSensingResistance 30K -200K (100ppm NH3 ) (200/50) NH3 Concentration Slope rate Temp: 20 2 Vc:5V Humidity: 65% 5% Vh: 5V time Over 24 hourDetecting concentrationscope 10ppm-300ppm NH310ppm-1000ppmBenzene10ppm-300ppmAlcoh ol D.
2 Structure and configuration, basic measuring circuit Structure and configuration of MQ-135 gas SENSOR is shown as Fig. 1 (Configuration A or B), SENSOR composed bymicro AL2O3 ceramic tube, Tin Dioxide (SnO2) sensitive layer, measuring electrode and heater are fixed into acrust made by plastic and stainless steel net. The heater provides necessary work conditions for work of sensitive PartsMaterials1 Gas sensing layerSnO22 ElectrodeAu3 Electrode linePt4 Heater coilNi-Cr alloy5 Tubular ceramicAl2O36 Anti-explosionnetworkStainless steel gauze(SUS316 100-mesh)7 Clamp ringCopper plating Ni8 Resin baseBakelite9 Tube PinCopper plating NiA A Fig. 1 Configuration AConfiguration The enveloped MQ-135 have 6 pin ,4 of them are used to fetch signals, and other 2 are used forproviding heating current. Electric parameter measurement circuit is shown as E. Sensitivity characteristic curve sensitivity characteristics of the MQ-135 SENSITVITY ADJUSTMENT Resistance value of MQ-135 is difference to various kinds and various concentration gases.
3 So,When usingthis components, sensitivity adjustment is very necessary. we recommend that you calibrate the detector for100ppm NH3 or 50ppm Alcohol concentration in air and use value of Load resistancethat( RL) about 20 K (10K to 47 K ). When accurately measuring, the proper alarm point for the gas detector should be determined afterconsidering the temperature and humidity 20. 40. 60. 811. 21. 41. 61. 8-20-100 102030405060degreeRs/Ro33%RH85% is shows the typicalsensitivity characteristics ofthe MQ-135 for several gases. in their: Temp: 20 Humidity: 65% O2 concentration 21% RL=20k Ro: SENSOR resistance at 100ppm of NH3 in the clean : SENSOR resistance at various concentrations of is shows the typical dependence ofthe MQ-135 on temperature and : SENSOR resistance at 100ppm of NH3 in air at 33%RH and 20 : SENSOR resistance at 100ppm of NH3 at different temperatures and 1110101001000ppmRs/RoAI RCO2CO NH4
