HANWEI ELECTRONICS CO.,LTD
MQ-5
http://www.hwsensor.com
TECHNICAL
DATA
MQ-5
GAS SENSOR
FEATURES
* High sensitivity to LPG, natural gas , town gas
* 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
LPG, natural gas , town gas, avoid the noise of alcohol and cooking fumes and cigarette smoke.
SPECIFICATIONS
A. Standard work condition
Symbol
Vc
V
H
P
L
R
H
P
H
Symbol
Tao
Tas
R
H
O
2
Parameter name
Circuit voltage
Heating voltage
Load resistance
Heater resistance
Heating consumption
Parameter name
Using Tem
Storage Tem
Related humidity
Oxygen concentration
Technical condition
5V±0.1
5V±0.1
20KΩ
31±10%
less than 800mw
Technical condition
-10℃-50℃
-20℃-70℃
less than 95%Rh
21%(standard condition)Oxygen
concentration can affect sensitivity
Technical parameter
10KΩ- 60KΩ
(5000ppm
methane
)
≤0.6
Vc:5V±0.1
Vh: 5V±0.1
Remarks
AC OR DC
ACOR DC
Room Tem
B. Environment condition
Remarks
minimum value is
over 2%
Remarks
Detecting concentration
scope：
200-10000ppm
LPG,LNG
N
atural gas,
C. Sensitivity characteristic
Symbol
Rs
α
(5000ppm/1000
ppm CH
4
)
Standard
detecting
condition
Preheat time
Parameter name
Sensing Resistance
Concentration slope rate
Temp: 20℃±2℃
Humidity: 65%±5%
iso-butane, propane
Town gas
Over 24 hour
D. Strucyure 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-5 gas sensor is shown as Fig. 1 (Configuration A or B), sensor composed by
TEL: 86-371- 67169070 67169080
FAX: 86-371-67169090
E-mail: sales@hwsensor.com
HANWEI ELECTRONICS CO.,LTD
MQ-5
http://www.hwsensor.com
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
sensitive components. The enveloped MQ-5 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
Fig.2
sensitivity characteristics of the MQ-5
10
MQ-5
Fig.3 is shows the typical
sensitivity characteristics of
the MQ-5 for several gases.
in their: Temp: 20℃、
Humidity: 65%、
O
2
concentration 21%
RL=20kΩ
Ro: sensor resistance at 1000ppm of
H
2
in the clean air.
Rs:sensor resistance at various
concentrations of gases.
H2
LPG
CH4
CO
alcohol
Air
Rs/Ro
1
0.1
100
1000
ppm
10000
MQ-5
1.5
1.4
1.3
1.2
1.1
1
0.9
0.8
0.7
0.6
0.5
-10
0
10
20
Temp
Fig.4
33%RH
85%RH
Fig.4 is shows the typical dependence of
the MQ-5 on temperature and humidity.
Ro: sensor resistance at 1000ppm of H
2
in air at
33%RH and 20 degree.
Rs: sensor resistance at different temperatures
and humidities.
Rs/Ro
30
40
50
SENSITVITY ADJUSTMENT
Resistance value of MQ-5 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 H
2
or LPG concentration in air and use value of Load resistance ( R
L
) about 20 KΩ(10KΩ to 47KΩ).
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
