Data Sheet

HANWEI ELECTRONICS CO.,LTD MQ-5 http://www.hwsensor.com
TEL: 86-371- 67169070 67169080 FAX: 86-371-67169090 E-mail: sales@hwsensor.com
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-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
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.
MQ-5
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
-10 0 10 20 30 40 50
Temp
Rs/Ro
33%RH
85%RH
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.
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.
Fig.4
MQ-5
0.1
1
10
100 1000 10000
ppm
Rs/Ro
H2
LPG
CH4
CO
alcohol
Air