Data Sheet

TECHNICAL DATA MQ-135 GAS SENSOR
FEATURES
Wide detecting scope Fast response and High sensitivity
Stable and long life Simple drive circuit
APPLICATION
They are used in air quality control equipments for buildings/offices, are suitable for detecting
of NH3,NOx, alcohol, Benzene, smoke,CO
2
,etc.
SPECIFICATIONS
A. Standard work condition
Symbol Parameter name Technical condition Remarks
Vc Circuit voltage 5V±0.1 AC OR DC
V
H
Heating voltage 5V±0.1 ACOR DC
R
L
Load resistance can adjust
R
H
Heater resistance 33Ω±5% Room Tem
P
H
Heating consumption less than 800mw
B. Environment condition
Symbol Parameter name Technical condition Remarks
Tao Using Tem -10-45
Tas Storage Tem
-20-70
R
H
Related humidity less than 95%Rh
O
2
Oxygen concentration 21%(standard condition)Oxygen
concentration can affect sensitivity
minimum value is
over 2%
C. Sensitivity characteristic
Symbol Parameter name Technical parameter Ramark 2
Rs Sensing
Resistance
30KΩ-200KΩ
(100ppm NH
3
)
α
(200/50)
NH
3
Concentration
Slope rate ≤0.65
Standard
Detecting
Condition
Temp: 20±2 Vc:5V±0.1
Humidity: 65%±5% Vh: 5V±0.1
Preheat time Over 24 hour
Detecting concentration
scope

10ppm-300ppm NH
3
10ppm-1000ppm
Benzene
10ppm-300ppm
Alcohol
D. Structure and configuration, basic measuring circuit
Structure and configuration of MQ-135 gas sensor is shown as Fig. 1
(Configuration A or B), sensor composed by
micro AL
2O3 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
Parts Materials
1Gas sensing
layer
SnO
2
2 Electrode Au
3 Electrode line Pt
4 Heater coil Ni-Cr alloy
5 Tubular ceramic Al
2
O
3
6 Anti-explosion
network
Stainless steel gauze
(SUS316 100-mesh)
7 Clamp ring Copper plating Ni
8 Resin base Bakelite
9 Tube Pin Copper plating Ni
AÏ ò
AÏ ò
Fig. 1
Configuration A Configuration B
Fig.2