... chip: the LM393, ZYMQ-2 gas sensorThird, the working voltage: DC 5 VoltIV characteristics:1, with the directions of the signal ... the concentration, the higher the voltage.5, liquefied petroleum gas, natural gas, city gas, better sensitivity.6, has a long life and reliable ... competition, product development, graduation design New MQ-2 smoke gas sensor module liquefied natural gas modules smoke module