HANWEI ELETRONICS CO.,LTD

MQ-8

http://www.hwsensor.com

TECHNICAL DATA

MQ-8

GAS SENSORFEATURES* High sensitivity to Hydrogen (H2)
* Small sensitivity to alcohol, LPG,cooking fumes* Stable and long life
APPLICATION
They are used in gas leakage detecting equipments in family and industry, are suitable fordetecting of Hydrogen (H2), avoid the noise of alcohol and cooking fumes, LPG,CO.
SPECIFICATIONS
A. Standard work condition
Symbol
Vc
VH
PL
RHPH

Parameter name
Circuit voltage
Heating voltage
Load resistanceHeater resistanceHeating consumption

B. Environment
Symbol
TaoTasRHO2Technical condition
5V±0.1
5V±0.110KΩ
31±5%less than800mW

Remarks
AC OR DCACOR DC
Room Temcondition

Parameter name
Using Tem
Storage Tem
Related humidity
Oxygen concentration

Technical condition-10℃-50℃-20℃-70℃
less than 95%Rh
21%(standard condition)Oxygen
concentration can affect sensitivity

Remarks

minimum value isover 2%

C. Sensitivity characteristic
SymbolRsα(1000ppm/500ppmH2)
Standard
detectingcondition
Preheat time

Parameter nameSensing ResistanceConcentration slope

Technical parameter
10KΩ- 60KΩ(1000ppm H2)≤0.6rate

Temp: 20℃±2℃
Humidity: 65%±5%Ramark 2
Detecting concentration
scope：100-10000ppm

Hydrogen (H2)

Vc:5V±0.1
Vh: 5V±0.1

Over 24 hour

D. Structure and configuration, basic measuring circuit

1234
56789Parts
Gas sensing
layerElectrode
Electrode line
Heater coil
Tubular ceramic
Anti-explosion
network
Clamp ringResin base
Tube Pin

Materials
SnO2
AuPt
Ni-Cr alloy
Al2O3
Stainless steel gauze(SUS316 100-mesh)
Copper plating Ni
Bakelite
Copper plating Ni

Fig.2
Fig. 1Configuration A

TEL: 86-371- 67169070

Configuration B67169080

A向A向FAX: 86-371-67169090

E-mail: sales@hwsensor.com

HANWEI ELETRONICS CO.,LTDMQ-8

http://www.hwsensor.com

Structure and configuration of MQ-8 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 acrust
made by plastic and stainless steel net. The heater provides necessary work conditions for work ofsensitive components. The enveloped MQ-8 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.2E. Sensitivity characteristic curve
MQ-8100Fig.3 is shows the typicalsensitivity characteristics ofthe MQ-8 for several gases.

Rs/Ro

101

in their: Temp: 20℃、
Humidity: 65%、
O2 concentration 21%
RL=10kΩ
Ro: sensor resistance at 1000ppm
H2 in the clean air.
Rs:sensor resistance at various
concentrations of gases.

H2LPG
CH40.1

COalcoholairppm

0.01
1001000

10000

Fig.2 sensitivity characteristics of the MQ-8

Rs/Ro

1.3
1.2
1.1
10.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0-10

MQ-8
Fig.4 is shows the typical dependence ofthe MQ-8 on temperature and humidity.

33%RH
85%RH
Fig.4
01020

Temp

30

40

Ro: sensor resistance at 1000ppm of H2 in air at
33%RH and 20 degree.
Rs: sensor resistance at 1000ppm of H2 in air
at different temperatures and humidities.

50

SENSITVITY ADJUSTMENT
Resistance value of MQ-8 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
1000ppm H2 concentration in air and use value of Load resistance ( RL) about 10 KΩ(5KΩ to 33 KΩ).
When accurately measuring, the proper alarm point for the gas detector should be determined after
considering the temperature and humidity influence.

TEL: 86-371- 67169070

67169080

FAX: 86-371-67169090

E-mail: sales@hwsensor.com