Zhengzhou Winsen Electronics Technology Co., Ltd
www.winsensor.com
MQ-5 Semiconductor Sensor for Combustible Gas
Sensitive material of MQ-5 gas sensor is SnO2, which with lower conductivity in clean air. When the target combustible gas exist, The sensor’s conductivity is more higher along with the gas concentration rising. Please use simple electrocircuit, Convert change of conductivity to correspond output signal of gas concentration.
MQ-5 gas sensor has high sensitity to Methane, Propane and Butane, and could be used to detect both Methane and Propane. The sensor could be used to detect different combustible gas especially Methane, it is with low cost and suitable for different application.
Character
Configuration
* Good sensitivity to Combustible gas in wide range * High sensitivity to Methane, Butane and Propane * Long life and low cost * Simple drive circuit
Application
* Domestic gas leakage detector * Industrial Combustible gas detector * Portable gas detector
Technical Data
Basic test loop
Model No. Sensor Type Standard Encapsulation Detection Gas
Concentration
Loop Voltage Vc
Circuit
Heater Voltage Load
Resistance
VH RL
Heater Resistance
RH
Character
Heater consumption
Sensing Resistance
PH Rs
Sensitivity S
Slope
α
Tem. Humidity
Condition Standard test circuit
Preheat time
MQ-5 Semiconductor Bakelite (Black Bakelite) LPG, Methane, coal gas 300-10000ppm( Methane, Propane, Butane, H2)
≤24V DC 5.0V±0.2V AC or DC
Adjustable
31Ω±3Ω Room Tem.
≤900mW
2KΩ-20KΩ(in 2000ppm C3H8 )
Rs(in air)/Rs(1000ppm C3H8)≥5 ≤0.6(R1000ppm/R500ppm H2)
20 ±2 65%±5%RH Vc:5.0V±0.1V VH: 5.0V±0.1V Over 48 hours
Vc VRL
RL VH
GND
The above is basic test circuit of the sensor. The sensor need to be put 2 voltage, heater voltage VH and test voltage VC . VH used to supply certified working temperature to the sensor, while VC used to detect voltage (VRL) on load resistance
RL whom is in series with sensor. The sensor has light polarity, Vc need DC power. VC and VH could use same power circuit with precondition to assure performance of sensor. In order to make the sensor with better performance, suitable RL value is needed: Power of Sensitivity body(Ps):
Tel: 86-371-67169097 Fax: 86-371-60932988
Email:
[email protected]
Zhengzhou Winsen Electronics Technology Co., Ltd
Ps=Vc2×Rs/(Rs+RL)2 Resistance of sensor(Rs): Rs=(Vc/VRL-1)×RL
www.winsensor.com
Sensitivity Characteristics
Influence of Temperature/Humidity
Fig.1 shows the typical sensitivity characteristics of the MQ-5, ordinate means resistance ratio of the sensor
(Rs/Ro), abscissa is concentration of gases. Rs means
resistance in different gases, Ro means resistance of sensor in 1000ppm H2. All test are under standard test conditions.
Structure and configuration
Fig.2 shows the typical temperature and humidity characteristics. Ordinate means resistance ratio of the sensor (Rs/Ro), Rs means resistance of sensor in 1000ppm Propane under different tem. and humidity. Ro means resistance of the sensor in environment of 1000ppm Propane, 20 /65%RH
Structure and configuration of MQ-5 gas sensor is shown as Fig. 3, sensor composed by 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-4 have 6 pin, 4 of them are used to fetch signals, and other 2 are used for providing heating current.
Tel: 86-371-67169097 Fax: 86-371-60932988
Email:
[email protected]
Zhengzhou Winsen Electronics Technology Co., Ltd
www.winsensor.com
Notification
1 Following conditions must be prohibited 1.1 Exposed to organic silicon steam
Organic silicon steam cause sensors invalid, sensors must be avoid exposing to silicon bond, fixature, silicon latex, putty or plastic contain silicon environment
1.2 High Corrosive gas
If the sensors exposed to high concentration corrosive gas (such as H2Sz, SOX Cl2 HCl etc), it will not only result in corrosion of sensors structure, also it cause sincere sensitivity attenuation.
1.3 Alkali, Alkali metals salt, halogen pollution
The sensors performance will be changed badly if sensors be sprayed polluted by alkali metals salt especially brine, or be exposed to halogen such as fluorin.
1.4 Touch water Sensitivity of the sensors will be reduced when spattered or dipped in water.
1.5 Freezing Do avoid icing on sensor’surface, otherwise sensor would lose sensitivity.
1.6 Applied voltage higher
Applied voltage on sensor should not be higher than stipulated value, otherwise it cause down-line or heater damaged, and bring on sensors’ sensitivity characteristic changed badly.
1.7 Voltage on wrong pins For 6 pins sensor, if apply voltage on 1 3 pins or 4 6 pins, it
will make lead broken, and without signal when apply on 2 4 pins
2 Following conditions must be avoided 2.1 Water Condensation
Indoor conditions, slight water condensation will effect sensor.