MQ-2 gas sensor using gas sensitive material is to be clean air in the lower conductivity of Tin oxide (SnO2). When the sensor when flammable gases are present in the environment in which the sensors conductivity with increasing concentration of combustible gas in the air increases.
Use a simple circuit to convert the changes in conductivity and output signal that 
corresponds to the concentration of the gas.
MQ-2 gas sensor higher sensitivity to liquefied petroleum gas, propane, hydrogen, detection of gas and other combustible vapors are ideal. This sensor can detect a variety of flammable gas, is a low-cost sensors for many applications.
Character Configuration
*Good sensitivity to Combustible gas in wide range
* High sensitivity to LPG, Propane and Hydrogen
* Long life and low cost
* Simple drive circuit
Application
* Domestic gas leakage detector
* Industrial Combustible gas detector
* Portable gas detector
Electronic Characteristics
| Items | Parameter name | Min | Type | Max | Unit |
| System Characteristics | |||||
| VCC | Working Voltage | 4.9 | 5 | 5.1 | V |
| PH | Heating consumption | 0.5 | – | 800 | mW |
| RL | Load resistance | can adjust | |||
| RH | Heater resistance | – | 33 | – | Ω |
| Rs | Sensing Resistance | 3 | – | 30 | kΩ |
Following conditions must be avoided
Water Condensation
Indoor conditions, slight water condensation will effect sensors performance lightly. However, if water condensation on sensors surface and keep a certain period, sensor’ sensitivity will be decreased.
Used in high gas concentration
No matter the sensor is electrified or not, if long time placed in high gas concentration, if will affect sensors characteristic.
Long time storage
The sensors resistance produce reversible drift if it’s stored for long time without electrify, this drift is related with storage conditions. Sensors should be stored in airproof without silicon gel bag with clean air. For the sensors with long time storage but no electrify, they need long aging time forstbility before using.
Long time exposed to adverse environment
No matter the sensors electrified or not, if exposed to adverse environment for long time, such as high humidity, high temperature, or high pollution etc, it will effect the sensors performance badly.
Vibration
Continual vibration will result in sensors down-lead response then repture. In transportation or assembling line, pneumatic screw driver/ultrasonic welding machine can lead this vibration.
Concussion
If sensors meet strong concussion, it may lead its lead wire disconnected.
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