HANWEI ELECTRONICS MQ-4 www.hwsensor.com TECHNICAL DATA MQ-4 GAS SENSOR FEATURES * High sensitivity to CHNatural gas. 4 * Small sensitivity to alcohol, smoke. * Fast response . * Stable and long life * Simple drive circuit APPLICATION They are used in gas leakage detecting equipments in family and industry, are suitable for detecting of CH ,Natural gas.LNG, avoid the noise of alcohol and cooking fumes and cigarette smoke. 4 SPECIFICATIONS A. Standard work condition Symbol Parameter name Technical condition Remarks Vc Circuit voltage 5V0.1 AC OR DC V Heating voltage 5V0.1 ACOR DC H P Load resistance 20K L R Heater resistance Room Tem 335% H P Heating consumption less than 750mw H B. Environment condition Symbol Parameter name Technical condition Remarks Tao Using Tem -10-50 Tas Storage Tem -20-70 R Related humidity less than 95%Rh H O Oxygen concentration 21%(standard condition)Oxygen minimum value is 2 concentration can affect sensitivity over 2% C. Sensitivity characteristic Symbol Parameter name Technical parameter Ramark 2 Rs Sensing Resistance 10K- 60K Detecting concentration (1000ppm CH ) scope 4 200-10000ppm CH , natural gas 4 Concentration slope rate 0.6 (1000ppm/ 5000ppm CH ) 4 Standard Temp: 202 Vc:5V0.1 detecting Humidity: 65%5% Vh: 5V0.1 condition Preheat time Over 24 hour D. Strucyure and configuration, basic measuring circuit Parts Materials 1 Gas sensing SnO 2 layer 2 Electrode Au 3 Electrode line Pt 4 Heater coil Ni-Cr alloy 5 Tubular ceramic Al O 2 3 6 Anti-explosion Stainless steel gauze network (SUS316 100-mesh) 7 Clamp ring Copper plating Ni 8 Resin base Bakelite 9 Tube Pin Copper plating Ni Fig.2 Fig. 1 Configuration A Configuration B A A TEL:86-371-67169080 FAX: 86-371-67169090 E-mail: sales hwsensor.com HANWEI ELECTRONICS MQ-4 www.hwsensor.com Structure and configuration of MQ-4 gas sensor is shown as Fig. 1 (Configuration A or B), sensor composed by micro AL2O3 ceramic tube, Tin Dioxide (SnO2) 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 sensitive components. The enveloped MQ-4 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 shown as Fig.2 E. Sensitivity characteristic curve MQ-4 10 Fig.3 is shows the typical sensitivity characteristics of the MQ-4 for several gases. in their: Temp: 20 Humidity: 65% O concentration 21% 2 RL=20k Ro: sensor resistance at 1000ppm of CH in the clean air. 4 1 Rs:sensor resistance at various LPG concentrations of gases. CH4 H2 CO alcohol smoke Air ppm 0.1 100 1000 10000 Fig.2 sensitivity characteristics of the MQ-4 MQ-4 1.4 33%RH Fig.4 is shows the typical dependence of 1.3 the MQ-4 on temperature and humidity. 85%RH 1.2 Ro: sensor resistance at 1000ppm of CH in air 4 1.1 at 33%RH and 20 degree. 1 Rs: sensor resistance at 1000ppm of CH in air 4 0.9 at different temperatures and humidities. 0.8 Fig.4 0.7 0.6 0.5 -10 0 10 20 30 40 50 Temp SENSITVITY ADJUSTMENT Resistance value of MQ-4 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 5000ppm of CH concentration in air and use value of Load resistance ( R ) about 20K(10K to 47K). 4 L When accurately measuring, the proper alarm point for the gas detector should be determined after considering the temperature and humidity influence. TEL:86-371-67169080 FAX: 86-371-67169090 E-mail: sales hwsensor.com Rs/Ro Rs/Ro