This post explains for the sensor. The MQ-6 gas sensor is a semiconductor-type sensor that detects flammable gases such as LPG, propane, and butane. Its sensing element is based on tin dioxide (SnO₂), whose conductivity increases when exposed to combustible gases.
The Part Number is MQ6.
The function of this semiconductor is GAS SENSOR.
The package is module type.
Manufacturer: HANWEI ( www.hwsensor.com )
Preview images:
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Description
Sensitive material of MQ6, MQ-6 gas sensor is SnO2, which with lower conductivity in clean air. When the target combustible gas exist, The sensor’s conductivity is more higher along with the gas concentration rising. Please use simple electrocircuit, Convert change of conductivity to correspond output signal of gas concentration.
Features
1. High sensitivity to LPG, iso-butane, propane
2. Small sensitivity to alcohol, smoke.
3. Fast response
4. Stable and long life
5. Simple drive circuit
Electrical & Mechanical Characteristics
| Parameter | Typical Value |
|---|---|
| Operating Voltage | 5 V ± 0.1 V |
| Heater Voltage (VH) | 5 V ± 0.2 V (AC/DC) |
| Load Resistance (RL) | 4.7 kΩ ~ 47 kΩ (external) |
| Heater Resistance (RH) | 31 Ω ± 3 Ω (room temp) |
| Heater Power | ≈ 900 mW |
| Preheat Time | > 24 hours (for first use) |
| Standard Detecting Range | 300 – 10,000 ppm (LPG, butane, propane) |
| Sensitivity (Rs/R0) | 2 ~ 20 (in 1000 ppm LPG) |
SENSITVITY ADJUSTMENT:
Resistance value of MQ-6 is difference to various kinds and various concentration gases. So, When using this components, sensitivity adjustment is very necessary. we recommend that you calibrate the detector for 1000ppm of LPG concentration in air and use value of Load resistance ( RL) about 20KΩ(10KΩ to 47KΩ). When accurately measuring, the proper alarm point for the gas detector should be determined after considering the temperature and humidity influence.

Advantages and Limitations
Advantages:
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Low cost, easy integration with microcontrollers (Arduino, STM32, etc.)
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Good sensitivity to LPG/butane/propane
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Fast response
Limitations:
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Requires long preheating time (≥24h initially, a few minutes on subsequent uses)
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Cross-sensitivity to alcohols, hydrogen, and smoke (not perfectly selective)
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Analog output requires calibration for accurate ppm readings
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Heater consumes relatively high power (~800–900 mW)
Applications
They are used in gas leakage detecting equipments in family and industry, are suitable for detecting of LPG, iso-butane, propane, LNG, avoid the noise of alcohol and cooking fumes and cigarette smoke.
