Target: CO,CH4
Model: MQ-9B
Detection range: CO(10-500ppm),CH4(300-10000ppm)
Detection principle: Semiconductor
Characteristics: Good sensitivity to CO
Size: φ16.7×9.4
Working conditions: Loop Voltage:5±0.1V
High temp.heater voltage:5±0.1V
Low temp.heater voltage:1.5±0.1V
Heater consumption:≤950mW
Notes: Low temperature 90s detection, high temperature 60s cleaning

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Sensitive material of MQ-9B gas sensor is SnO2, which with lower conductivity in clean air. It detects carbon monoxide (1.5V) by method of cycle high and low temperature. At high temperature (5.0V), it can detect CO as well as clean the other gases adsorbed at low temperature. The sensor’s conductivity gets higher along with the CO and CH4 gas concentration rising. Users can convert the change of conductivity to correspond output signal of gas concentration through a simple circuit.


It is widely used in the CO CH4 gas leakage alarm of civil, home kitchen and industrial and portable gas detector.


It has good sensitivity to carbon monoxide and methane in wide range, and has advantages such as long lifespan, low cost and simple drive circuit &etc.


Model MQ-9B
Sensor Type Semiconductor
Standard Encapsulation Plastic cap
Target Gas Carbon Monoxide, Methane
Detection range 10~500ppm CO,300~10000ppm CH4
Standard Circuit Conditions Loop Voltage Vc 5.0V±0.1V DC
Heater Voltage VH 5.0V±0.1V AC or DC (High temp.) 1.5V±0.1V AC or DC (Low temp.)
Heater Time TL 60S±1S (High temp.);90S±1S (Low temp.)
Load resistance RL Adjustable
Sensor character under standard test conditions Heater Resistance RH 30Ω±3Ω(room temp.)
Heater consumption PH ≤950mW
Sensitivity S Rs(in air)/Rs(in 150ppm CO)≥5 Rs(in air)/Rs(in 5000ppm CH4)≥3
Output Voltage Vs 2.5V~4.3V (in 150ppm CO) 2.0V~4.0V (in 5000ppm  CH4)
Concentration Slope α ≤0.6(R300ppm/R50ppmCO) ≤0.6(R5000ppm/R1000ppmCH4)
  Standard test conditions Tem.  Humidity 20℃±2℃;55%±5%RH
Standard test circuit Vc:5.0V±0.1V; VH(High temp.):5.0V±0.1V; VH(Low temp.):1.5V±0.1V
Preheat time Over 48 hours
O2content 21%(not less than 18%) O2 concentration effects initial value, sensitivity and repeatability.
Life span 10 years

* The description and specifications might be changed without notice. Please contact us for the latest information before placing orders.

Technical Support:

Customized technical design and function, LOGO and package are available without extra charge (including molding fee) for mass volume.

The sensors don't have sleeping mode. It can be set in program if needed.

All Winsen products go through strict inspections and tests to make sure they are 100% qualified before shipping out.

The sensor has been fully tested (not calibrated) before leaving the factory. However, after transportation and storage, the environment conditions change, and the surface of the sensor absorbs moisture, mixed gas, pollution matters, etc. It is recommended that customers perform aging and calibration after sensors become stable according to the program and use occasions of the whole device.

15﹪-90﹪RH without condensation,greater or less than this range or long-term high temperature and high humidity will affect the life of the sensor.

Our sensors are certified with CE, 3C, ROHS, anti-explosion, fire prevention, and coal mining safety according to different applications. And we provide assistance for new certification.

Many factors can cause the sensor to fail such as broken wires in transportation, poisoning, falling off of the sensitive material, damage to the heating wire (device), etc. Please find specific cause in each category with Winsen’s aftersales.

Winsen provides professional consultation and service before and after sales. We will recommend the best fitting sensor for your demand. If you have any problem, don’t hesitate to email us to

Due to high volume of daily incoming emails and time zone difference, we may not be able to reply your emails immediately. But we will reply to your inquiry in 24 business hours.