MQ-2 गैस सेंसर मॉड्यूल (4-पिन) पिनआउट

पिन

VCC (5V — the heater draws ~150mA)
GND
DO (digital out — the LM393 comparator pulls it LOW when AO crosses the threshold set by the trimmer; the DO LED lights at the same time)
AO (analog out — rises with gas concentration)

सप्लाई वोल्टेज	5 V
Heater resistance	33 Ω ±5 %
Heater current	≈150 mA
Target gases	LPG, propane, butane, methane, hydrogen, alcohol, smoke
Detection range	300–10000 ppm (combustible gases)
Outputs	AO analog 0–5 V + DO digital (LM393 comparator, active LOW)
Preheat	≥ 24 h first use; ≈1 min per power-up
आउटपुट प्रकार	Relative — needs calibration for ppm

Needs a burn-in warm-up (24–48h first use, ~1 min per power-up) before readings settle.
Turning the trimmer clockwise raises the threshold (less sensitive DO). AO is unaffected by the trimmer.