... height 27mmSecond, the main chip: the LM393, ZYMQ-2 gas sensorThird, the working voltage: DC 5 VoltIV characteristics:1, with the ... signal output.2, two-way signal output (analog output, and TTL level output)3, TTL output valid signal is low. ( ... : SCM learning, electronic competition, product development, graduation design New MQ-2 smoke gas sensor module liquefied natural gas modules smoke module