henan hanwei electronics co., ltd www.hwsensor.com tel: 86-371-67169070/80 fax: 86-371-67169090 email: sales@hwsensor.com MQ131 semiconducto r sensor for ozone sensitive material of MQ131 gas sensor is sno 2, which with lower conductivity in clean air. when ozone gas exists. the sensor ?s conductivity is more higher alon g with the gas c oncentration rising. please use simple electrocircuit , convert change of conductivity to correspond output signal of gas concentration. MQ131 gas sensor has high sens itity to ozone, also sensit ive to cl2, no2, etc. character configuration * good sensitivity to ozone in wide range * high sensitivity to ozone * long life and low cost * simple drive circuit application * domestic ozone concentra tion overload detector * industrial ozone concentra tion overload detector * portable ozone concentra tion overload detector technical data basic test loop the above is basic test circuit of the sensor. the sensor need to be put 2 voltage, heater voltage vh and test voltage vc . vh used to supply certified working temperature to the sensor, while vc used to detect voltage (vrl) on load resistance rl whom is in series with sensor. the sensor has light polarity, vc need dc power. vc and vh could use same power circuit with precondition to assure performance of sensor. in order to make the sensor with better performance, suitable rl value is needed: power of sensitivity body(ps): ps=vc 2 rs/(rs+rl) 2 resistance of sensor(rs): rs=(vc/vrl-1)rl model no. MQ131 sensor type semiconductor standard encapsulation bakelite (black bakelite) detection gas ozone concentration 10-1000ppm ozone loop voltage v c 24v dc heater voltage v h 5.0v0.2v ac or dc circuit load resistance r l adjustable heater resistance r h 31 ? 3 ? room tem. heater consumption p h 900mw sensing resistance r s 50k ? -500k ? (in 50ppm o 3 ) sensitivity s rs(in air)/rs(in 50ppm o 3 ) 3 character slope (r 50ppm /r 10ppm o 3 ) tem. humidity 20 2 65%5%rh standard test circuit vc:5.0v0.1v v h : 5.0v0.1v condition preheat time over 48 hours vc v h gnd r l v rl free datasheet http:///
henan hanwei electronics co., ltd www.hwsensor.com tel: 86-371-67169070/80 fax: 86-371-67169090 email: sales@hwsensor.com sensitivity characteristics influence of temperature/humidity fig.1 shows the typical sensitivity characteristics of fig.2 shows the typical temperature and humidity the MQ131, ordinate means resistance ratio of the sensor characteristics. ordinate means resistance ratio ( rs/ro ), abscissa is concentration of gases. rs means of the sensor (rs/ro), rs means resistance of sensor resistance in different gases, ro means resistance of in 50ppm ozone under different tem. and humidity. sensor in 50ppm cl2. all test are under standard ro means resistance of the sensor in environment of test conditions. 50ppm ozone, 20 /65%rh structure and configuration structure and configuration of mq 131 gas sensor is shown as fig. 3, 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. t he enveloped mq-4 have 6 pin, 4 of them are used to fetch signals, and other 2 are used for providing heating current. free datasheet http:///
henan hanwei electronics co., ltd www.hwsensor.com tel: 86-371-67169070/80 fax: 86-371-67169090 email: sales@hwsensor.com notification 1 following conditions must be prohibited 1.1 exposed to organic silicon steam organic silicon steam cause sens ors invalid, sensors must be avoid exposing to silicon bond, fixature, silicon latex, putty or pl astic contain silicon environment 1.2 high corrosive gas if the sensors exposed to high concentration corro sive gas (such as h 2 sz, so x , cl 2 , hcl etc), it will not only result in corrosion of sensors structure, also it cause sincer e sensitivit y attenuation. 1.3 alkali, alkali metals salt, halogen pollution the sensors performance will be changed badly if s ensors be sprayed polluted by alkali metals salt especially brine, or be expos ed to halogen such as fluorin. 1.4 touch water sensitivity of the sens ors will be reduced when spattered or dipped in water. 1.5 freezing do avoid icing on sensor?surface, other wise sensor would lose sensitivity. 1.6 applied voltage higher applied voltage on sensor should not be higher than stipulated value, ot herwise it cause down-line or heater damaged, and bring on sensors? sens itivity characteristic changed badly. 1.7 voltage on wrong pins for 6 pins sensor, if apply voltage on 1 3 pins or 4 6 pins, it will make lead broken, and wi thout signal when apply on 2 4 pins 2 following conditions must be avoided 2.1 water condensation indoor conditions, slight water c ondensation will effect sensors perfo rmance lightly. however, if water condensation on sensors surf ace and keep a certain period, sensor ? sensitivity will be decreased. 2.2 used in high gas concentration no matter the sensor is electrified or not, if l ong time placed in high gas c oncentration, if will affect sensors characteristic. 2.3 long time storage the sensors resistance produce reversib le drift if it?s stored for long time without electrify, this drift is related with storage conditions. sens ors should be stored in ai rproof without silicon gel bag with clean air. for the sensors with long time stor age but no electrify, they need long aging time for stbility before using. 2.4 long time exposed to adverse environment no matter the sensors electrified or not, if ex posed to adverse environment for long time, such as high humidity, high temperature, or high pollution et c, it will effect the sensors performance badly. 2.5 vibration continual vibration will result in sensors down- lead response then repture. in transportation or assembling line, pneumatic screwdri ver/ultrasonic welding machine can lead this vibration. 2.6 concussion if sensors meet strong conc ussion, it may lead its lead wire disconnected. 2.7 usage for sensor, handmade welding is optimal way. if us e wave crest welding should meet the following conditions: 2.7.1 soldering flux: rosin solder ing flux contains least chlorine 2.7.2 speed: 1-2 meter/ minute 2.7.3 warm-up temperature: 10020 2.7.4 welding temperature: 25010 2.7.5 1 time pass wave crest welding machine if disobey the above using terms, sensors sensitiv ity will be reduced. free datasheet http:///
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