hanwei elec tronics co.,ltd mq - 136 http://www.hwsensor.com tel: 86 - 371 - 5333098 5333099 fax: 86 - 371 - 5333090 e - mail: sensor@371.net technical data mq - 136 gas sensor features 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 sui table for detecting of h 2 s. specifications a. standard work condition symb o l parameter name technical condition remarks vc circuit voltage 5v0.1 ac or dc v h heating voltage 5v0.1 acor dc r l load resistance can adjust r h heater res istance 31 |?? 5% room tem p h heating consumption less than 800mw b. e n viro n ment condition symbol parameter name technical condition remarks tao u s ing tem - 10 ?? - 45 ?? tas storage tem - 20 ?? - 70 ?? r h related humidity less than 95%rh o 2 o xygen concentration 21%(standard condition)oxygen concentration can affect sensitivity minimum value is over 2% c. sensitivity characteristic symbol parameter name technical parameter ramark 2 rs sensing resistance 30 k |? - 200 k |? (10ppm h 2 s ) | (20/5) h 2 s concent rat ion slope rate ? 0.65 standard detecting condition temp: 20 ??? 2 ?? vc:5v0.1 humidity: 65%5% vh: 5v0.1 preheat time over 24 hour detecting concentration scope o 1 - 100ppm h 2 s d. structure and configuration, basic measuring circuit structure and configuration of mq - 136 gas sensor is show n as fig. 1 ( configuration a or b), sensor composed by micro al 2 o 3 ceramic tube, tin dioxide (sno 2 ) sensitive layer, measuring electrode and heater are fixed into a crust made by plastic and stainless steel net. the heater provides necessary work conditions for work of parts materials 1 gas sensing layer sno 2 2 electrode au 3 electrode line pt 4 heater coil ni - cr alloy 5 tubular ceramic al 2 o 3 6 anti - explosion network stainless steel gauze (sus316 100 - mesh) 7 clamp ring copper plating ni 8 resin base bakelite 9 tube pin copper plating ni a? a? fig. 1 configuration a configuration b fig .2
hanwei elec tronics co.,ltd mq - 136 http://www.hwsensor.com tel: 86-371-65333098 65333099 fax: 86-371-65333090 e - mail: sensor@371.net sensitive components. the enveloped mq - 136 have 6 pin , 4 of them are used to fetch signals, and other 2 are used for providing heating current. electric parameter measurement circuit is show n as fig.2 e. sensitivity characteristic curve fig.3 sensitivity characteristics of the mq - 136 sensitvity adjustment resistance value of mq - 136 is difference to various kinds and various concentration gases. so, when using this components, sensitivity adjustment is very necessary. we recommend that you calibrate the detector for 10ppm h 2 s concen tration in air and use value of load resistance that( r l ) about 20 k |? (10k |? to 47 k |? ). when accurately measuring, the proper alarm point for the gas detector should be determined after considering the temperature and humidity influence. 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 -20 -10 0 10 20 30 40 50 60 degree rs/ro 33%rh 85%rh fig.3 is shows the typical sensitivity characteristics of the mq - 136 for several gases. in their: temp: 20 ??? humidity: 65% ? o 2 concentration 21% rl=20k |? r o: sensor resistance at 10ppm of h 2 s in the clean air. rs: sensor resistance at various concentrations of gases. fig.4 is shows the typical dependence of the mq - 136 on temperature and humidity. r o: sensor resistance at 10ppm of h 2 s at 33%rh and 20 degree. rs: sensor resistance at 10ppm of h 2 s at different te mperatures and humidity. fig.4
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