MQ-2 smoke gas sensor module liquefied natural gas modules smoke module Product DescriptionFREE SHIPPING 100% New MQ2 MQ-2 LPG I-butane Propane Methane Alcohol Hydrogen Smoke Gas Sensor Module Long Size: 32mm x width 22mm X height 27mmSecond, the main chip: the LM393, ZYMQ-2 gas sensorThird, the working voltage: DC 5 VoltIV characteristics:1, with the directions of the signal output.2, two-way ...