MQ-138

HANWEI ELECTRONICS CO.,LTD TECHNICAL DATA MQ-138 http://www.hwsensor.com MQ-138 GAS SENSOR FEATURES Wide detecting scope Fast response and High sensitivity Stable and long life Simple drive circuit APPLICATION They are used in Breath alcohol detector, solvent detectors ,Air quality control equipments for buildings/offices, are suitable for detecting of n-Hexane, Benzene, NH3, alcohol, ,smoke, CO ,etc. SPECIFICATIONS A. Standard work condition Symbol Vc VH Parameter name Circuit voltage Heating voltage Technical condition 5V±0.1 5V±0.1 Remarks AC OR DC ACOR DC RL Load resistance RH Heater resistance can adjust 31Ω±3Ω Room Tem PH Heating consumption less than 850mw B. Environment condition Symbol Parameter name Technical condition Remarks Tao Using Tem -10℃-45℃ Tas Storage Tem -20℃-70℃ RH Related humidity less than 95%Rh O2 Oxygen concentration 21%(standard condition)Oxygen minimum value is concentration can affect over 2% sensitivity C. Sensitivity characteristic Symbol Parameter name Technical parameter Remarks Rs Sensing Resistance 20KΩ-200KΩ (1000ppm Benzene ) Detecting concentration scope： 10ppm-1000ppm α (200/50) Concentration Slope rate ≤0.65 Benzene 10ppm-1000ppm NH3 Standard Detecting Condition Temp: 20℃±2℃ Vc:5V±0.1 Humidity: 65%±5% Vh: 5V±0.1 Alcohol 10ppm-3000ppm NH3 Preheat time Over 24 hours D. Structure and configuration, basic measuring circuit Parts 1 Gas sensing layer 2 Electrode 3 Electrode line 4 Heate...