MQ-7B Carbon Monoxide Sensor

The gas sensing material used in the MQ-7B carbon monoxide gas sensor is tin dioxide (SnO2), which has a low conductivity in clean air. The high and low temperature cycle detection method is used to detect carbon monoxide at low temperature (1.5V heating). The change in conductivity can be converted into an output signal corresponding to the gas concentration using a simple circuit.

The MQ-7B carbon monoxide gas sensor has high sensitivity to carbon monoxide. This sensor can detect a variety of carbon monoxide-containing gases and is a low-cost sensor suitable for a variety of applications.


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Sensor Features
Good sensitivity to carbon monoxide gas

Long life and low cost

A simple drive circuit can


main application
Household Gas Leak Alarm

Industrial carbon monoxide gas alarm

Portable Gas Detector


Technical indicators

Product number

MQ-7B Carbon Monoxide Sensor

product type

Semiconductor gas sensor

standard package

plastic seal

detect gas

carbon monoxide

Detection concentration

10-500ppm CO

Standard Circuit Conditions

loop voltage


≤24V  DC

heating voltage


5.0V±0.1V ACorDC(high temperature) 1.5V±0.1V ACorDC(low temperature)

heating time


60±1S(high temperature)90±1S(low temperature)

Load Resistance



Component characteristics under standard test conditions

heating resistance


29Ω±3Ω(room temperature)

Heating power consumption



The output voltage





Rs(in air)/Rs(150ppmCO)≥5

Concentration slope


≤0.6(R300ppm/R50ppm CO)

Standard Test Conditions

temperature humidity


Standard Test Circuit

Vc:5.0V±0.1V; VH(high temperature): 5.0V±0.1V; VH(low temperature): 1.5V±0.1V

Preheat time

Not less than 48 hours

oxygen content

21% (not less than 18%, the oxygen concentration will affect the initial value, sensitivity and repeatability of the sensor, please consult when using it under low oxygen concentration)


10 years

Note: The output voltage (Vs) refers to the VRL in the test atmosphere

production workshop


patent certificate

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