MQ3 - Alcohol Sensing Module

• It is suitable for detecting Alcohol, Benzine, CH4, Hexane, LPG, CO. Due to its high sensitivity and fast response time, measurements can be taken as soon as possible. The sensitivity of the sensor can be adjusted by using the potentiometer.

FEATURES

High sensitivity to alcohol and small sensitivity to Benzine .

Fast response and High sensitivity  

Stable and long life    

Simple drive circuit APPLICATION    

They are suitable for alcohol checker,Breathalyser.

Structure and configuration of MQ-3 gas sensor is shown as Fig. 1 (Configuration A or B), sensor composed by micro AL2O3 ceramic tube, Tin Dioxide (SnO2) sensitive layer, measuring electrode and heater are fixed into a crust made by plastic and stainless steel net. The heater provides necessary work conditions for work of sensitive components. The enveloped MQ-3 have 6 pin ,4 of them are used to fetch signals, and other 2 are used for providing heating current.
Electric parameter measurement circuit is shown as Fig.2

SENSITVITY ADJUSTMENT
Resistance value of MQ-3 is difference to various kinds and various concentration gases. So,When using this components, sensitivity adjustment is very necessary. we recommend that you calibrate the detector for 0.4mg/L ( approximately 200ppm ) of Alcohol concentration in air and use value of Load resistancethat( RL) about 200 KΩ(100KΩ to 470 KΩ). When accurately measuring, the proper alarm point for the gas detector should be determined after considering the temperature and humidity influence.