Alcohol Gas Sensor - MQ-3

MQ-3 Alcohol Gas sensor is a gas sensor that can detect alcohol gas between 0.04mg/L and 4mg/L in the environment and can be used in making an alcohol meter. It gives an analog output according to the gas density in the environment.

There are A,B,H pins on the sensor. The sensor can be operated by applying the connection diagram below. Sensitivity can be changed by changing the connected resistor value. As an example, you can use a 200 kΩ resistor.