MQ-3B Alcohol Sensor

The gas sensing material used in the MQ-3B alcohol gas sensor is tin dioxide (SnO2), which has a low conductivity in clean air. When there is alcohol vapor in the environment where the alcohol sensor is located, the conductivity of the gas sensor increases with the increase of the alcohol gas concentration in the air. The change in conductivity can be converted into an output signal corresponding to the gas concentration using a simple circuit.

MQ-3B semiconductor alcohol sensor has high sensitivity to alcohol and can resist the interference of gasoline, smoke and water vapor. This gas sensor can detect alcohol atmospheres of various concentrations and is a low-cost sensor suitable for a variety of applications.


Related Products


Sensor Features
This product has good sensitivity to alcohol in a wide concentration range. It has the advantages of long life, low cost and simple driving circuit.


main application
Widely used in automotive alcohol gas alarms, industrial alcohol gas alarms and portable gas detectors.


Technical indicators

Product number

MQ-3B Alcohol Sensor

product type

Semiconductor gas sensor

standard package

plastic seal

detect gas

alcohol steam

Detection concentration

25~500ppm Alcohol

Standard Circuit Conditions

loop voltage


≤24V  DC

heating voltage


5.0V±0.1V AC or DC

Load Resistance



Gas sensor characteristics under standard test conditions

heating resistance


29±3Ω(room temperature)

Heating power consumption



The output voltage


 2.5V-4.0V (in 125ppm Alcohol)



Ro(in air)/Rs(125ppm Alcohol)≥5

Concentration slope


≤0.6(R300ppm/R50ppm Alcohol)

 Standard Test Conditions

temperature humidity


Standard Test Circuit


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 year

Note: The output voltage (Vs) refers to the VRL in the test atmosphere
Note: Product parameters are subject to change without prior notice

production workshop


patent certificate

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