9Pcs MQ2 MQ 3 MQ 4 MQ 5 MQ 6 MQ 7 MQ 8 MQ 9 MQ 135 Sensor Module ForWe will default sending carton package to replace the plastic box but there may some stocks are still packaging with plastic box please note about this before you buy it Feature MQ 2 Detection concentration 300 1000ppm combustible gas MQ 3 Used in motor vehicles and other no drunken drivers homework personnel on site testing also used in other places of ethanol vapor detection Feature Size 32 x 22 x 27mmMain chip LM393 ZYMQ 3 gas sensorsWorking voltage DC 5V1 With a signal output instructions 2 Two way signal output TTL level output and analog output 3 TTL output signal for low level effectively when the low output electric signal lights at ordinary times can be directly by single chip microcomputer 4 Analog 0 5V voltage the higher the concentration the higher the voltage 5 To ethanol steam has a high sensitivity and good selectivity 6 In June and has long service life and reliable stability 7 Rapid response recovery features MQ 4 1 Using high quality dual panel design with power indicator and TTL signal output instructions 2 With a DO switch signal TTL output and AO analog signal output 3 TTL output valid signal is low When the output low signal light can be directly connected microcontroller or relay module 4 The analog output voltage the higher the concentration the higher the voltage 5 Methane natural gas has better detection sensitivity 6 There are four screw holes