The MQ-2 gas sensor is a device that can detect a variety of gases, including flammable gases such as propane and methane, as well as smoke. It is commonly used in applications such as gas leak detectors, safety devices, and industrial control systems. The MQ-2 sensor operates by using a chemical reaction between the target gas and conductive metal oxide to produce a current.

The magnitude of the current is proportional to the concentration of the target gas in the air. The gas sensor can be used to detect a wide range of gas concentrations, depending on the specific type of gas being detected. It is important to note that the MQ-2 sensor is not selective for specific gas and may be triggered by other gases as well. It is recommended to use the MQ-2 sensor with caution and to take appropriate safety measures when working with it.