HANWEI ELETRONICS CO.,LTD
MQ-2
http://www.hwsensor.com
TECHNICAL
DATA
MQ-2
GAS SENSOR
FEATURES
Wide detecting scope
Fast response and High sensitivity
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 LPG, i-butane, propane, methane ,alcohol, Hydrogen, smoke.
SPECIFICATIONS
A. Standard work condition
Symbol
Vc
V
H
R
L
R
H
P
H
Symbol
Tao
Tas
R
H
O
2
Parameter name
Circuit voltage
Heating voltage
Load resistance
Heater resistance
Heating consumption
Technical condition
5V±0.1
5V±0.1
can adjust
33Ω±5%
less than 800mw
Technical condition
-20℃-50℃
-20℃-70℃
less than 95%Rh
21%(standard condition)Oxygen
concentration can affect sensitivity
Technical parameter
3KΩ-30KΩ
(1000ppm iso-butane )
Remarks
AC OR DC
ACOR DC
Room Tem
B. Environment condition
Parameter name
Using Tem
Storage Tem
Related humidity
Oxygen concentration
Remarks
minimum value is
over 2%
Remarks
Detecting concentration
scope：
200ppm-5000ppm
LPG and propane
300ppm-5000ppm
butane
5000ppm-20000ppm
methane
300ppm-5000ppm H
2
100ppm-2000ppm
Alcohol
C. Sensitivity characteristic
Symbol
Rs
Parameter name
Sensing
Resistance
Concentration
Slope rate
Temp: 20℃±2℃
Humidity: 65%±5%
α
(3000/1000)
isobutane
Standard
Detecting
Condition
Preheat time
≤0.6
Vc:5V±0.1
Vh: 5V±0.1
Over 24 hour
D. Structure and configuration, basic measuring circuit
1
2
3
4
5
6
7
8
9
Parts
Gas sensing
layer
Electrode
Electrode line
Heater coil
Tubular ceramic
Anti-explosion
network
Clamp ring
Resin base
Tube Pin
Materials
SnO
2
Au
Pt
Ni-Cr alloy
Al
2
O
3
Stainless steel gauze
(SUS316 100-mesh)
Copper plating Ni
Bakelite
Copper plating Ni
Fig.2
Fig. 1
Configuration
A
Configuration
B
A向
A向
Structure and configuration of MQ-2 gas sensor is shown 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
TEL: 86-371- 67169070 67169080
FAX: 86-371-67169090
E-mail: sales@hwsensor.com
HANWEI ELETRONICS CO.,LTD
MQ-2
http://www.hwsensor.com
crust
made by plastic and stainless steel net. The heater provides necessary work conditions for work of
sensitive components. The enveloped MQ-2 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
10
MQ-2
Fig.3 is shows the typical
sensitivity characteristics of
the MQ-2 for several gases.
in their: Temp: 20℃、
Humidity: 65%、
O
2
concentration 21%
RL=5kΩ
Ro: sensor resistance at 1000ppm of
H
2
in the clean air.
Rs:sensor resistance at various
concentrations of gases.
Rs/Ro
1
H2
LPG
CH4
CO
alcohol
smoke
propane
air
ppm
1000
10000
0.1
100
Fig.2
sensitivity characteristics of the MQ-2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
-20
-10
0
10
20
30
40
50
60
Rs/Ro
33%RH
85%RH
Fig.4 is shows the typical dependence of
the MQ-2 on temperature and humidity.
Ro: sensor resistance at 1000ppm of H
2
in air
at 33%RH and 20 degree.
Rs: sensor resistance at 1000ppm of H
2
at different temperatures and humidities.
Fig.4
degree
SENSITVITY ADJUSTMENT
Resistance value of MQ-2 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 liquified petroleum gas<LPG>,or 1000ppm iso-butane<i-C
4
H
10
>concentration in air and use value
of
Load resistance that( R
L
) about 20 KΩ(5KΩ to 47 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
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