MQ2 Gas sensor is a Metal Oxide Semiconductor (MOS) type Gas Sensor mainly used to detect gases like Methane, Butane, LPG, Smoke, etc. It is also known as Chemiresistors as the gas detection is based on the change of resistance of the sensing material when the Gas comes in to contact. If you want to measure a different type of Gas you can check these Gas Sensors. 

MQ2 Gas sensor module works on 5V DC and uses around 800mW. It can detect LPG, Smoke, Alcohol, Propane, Hydrogen, Methane and Carbon Monoxide concentrations in a range of 200 to 10000 ppm.

MQ2 Gas Sensor Features & Specifications

• Operating Voltage is +5V
• Analog output voltage: 0V to 5V
• Digital Output Voltage: 0V or 5V (TTL Logic)
• Preheat duration 20 seconds
• Can be used as a Digital or analog sensor
• The Sensitivity of Digital pin can be varied using the potentiometer