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MQ9 CO Flammable Gas Sensor Module

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Series MQ gas sensors
MQ9 CO Flammable Gas Sensor Module Datasheet

MQ9 overview

MQ9 gas sensor belongs to the MQ sensor family series designated for the detection and identification of flammable and combustible gases. The module can detect flammable and carbon monoxide gas in the range of 10 - 10000ppm. Its most common application is in the field of domestic gas leakage alarms and detectors with a high sensitivity to propane and smoke.

The sensing material of the MQ9 gas sensor is SnO2, which with lower conductivity in clean air. It makes detection by method of cycle high and low temperature and detects CO when low temperature (heated by 1.5V). The sensor’s conductivity is higher along with the gas concentration rising. When the high temperature (heated by 5.0V), it detects Methane, Propane, etc. combustible gas, and cleans the other gases adsorbed under low temperature. Please use a simple electro circuit, to convert the change of conductivity to the corresponding output signal of gas concentration. MQ9 gas sensors must always be avoided to be used in an environment where either a highly corrosive gas or organic silicon steam has been permutated as it interferes and can potentially destroy the sensing element of the MQ9 sensing module.

MQ9 CO Flammable Gas Sensor Module-Pinout

Key specifications

Detection Gas
Carbon Monoxide and Flammable Gas
Concentration
10-10000ppm CO, 100-10000ppm Combustible Gas
Supply Voltage
<10V
Heater Voltage
5.0V ± 0.2V (High), 1.5V ± 0.1V (Low)
Load Resistance
Adjustable
Heater Resistance
31Ω ± 3Ω
Standard Encapsulation
Bakelite
Loop Voltage Vc
≤10V DC

Datasheet

mq9.pdf
Format PDFSize 176 KBLanguage EN
Third-party / unverified source

MQ9 features

  • High sensitivity to Methane, Propane, and CO
  • Long life and low cost
  • ESD Protection
  • Overvoltage Protection
  • Early warning triggers for harmful fumes
  • Fast response time
  • Simple drive circuit

MQ9 pinout

MQ9 pinout diagram
PinNameDescription
1VCCThis pin powers the module, typically the operating voltage is +5V
2GNDUsed to connect the module to the system ground
3DOYou can also use this sensor to get digital output from this pin, by setting a threshold value using the potentiometer
4AOThis pin outputs 0-5V analog voltage based on the intensity of the gas.

MQ9 specifications

Detection Gas Carbon Monoxide and Flammable Gas
Concentration 10-10000ppm CO, 100-10000ppm Combustible Gas
Supply Voltage <10V
Heater Voltage 5.0V ± 0.2V (High), 1.5V ± 0.1V (Low)
Load Resistance Adjustable
Heater Resistance 31Ω ± 3Ω
Standard Encapsulation Bakelite
Loop Voltage Vc ≤10V DC
Heater Voltage VH 5.0V±0.2V AC or DC (High)/ 1.5V±0.1V AC or DC (Low)
Sensing Resistance Rs 2KΩ-20KΩ(in 100ppm CO )
Heater Consumption <350mW

MQ9 applications

  • Domestic gas leakage detector
  • Industrial gas detector
  • Portable gas detector

More about MQ9

MQ9 datasheet PDF preview

PDF · 176 KB

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