Zhengzhou Winsen Electronics Technology Co., Ltd
www.winsen-sensor.com
Tel: 86-371-67169097/67169670 Fax: 86-371-60932988 Email:
Basic Circuit
Fig2. MQ135 Test Circuit
Instructions:
The above fig is the basic test circuit of MQ135.The sensor requires two voltage inputs:
heater voltage (V
H
) and circuit voltage(V
C
). V
H
is used to supply standard working temperature to the
sensor and it can adopt DC or AC power, while V
RL
is the voltage of load resistance R
L
which is in series with
sensor. Vc supplies the detect voltage to load resistance R
L
and it should adopts DC power.
Description of Sensor Characters
Fig3.Typical Sensitivity Curve
The ordinate is resistance ratio of the sensor (Rs/R
0
), the
abscissa is concentration of gases. Rs means resistance in
target gas with different concentration, R
0
means
resistance of sensor in clean air. All tests are finished
under standard test conditions.
Fig4.Typical temperature/humidity characteristics
The ordinate is resistance ratio of the sensor (Rs/Rso).Rs
means resistance of sensor in 400ppm H
2
gas under
different tem. and humidity. Rso means resistance of the
sensor in 400ppm H
2
gas under 20
℃
/55%RH.
H
2
Air
NH
3
Toluene
Concentration (ppm)