MQ-3 GAS SENSOR

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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.


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.