Catalytic Combustion Method Sensor is the most widely used gas sensor specifically designed for detecting various combustible gases. It detects gases based on the heat generated from the combustion of combustible gases on oxidation catalysts. This sensor demonstrates excellent performance in responsiveness, accuracy, and reproducibility due to its high reaction rate.

When powered, the precious metal coil inside the sensor heats the detection element to 300-450°C. Combustible gases burn on the surface of the detection element, raising its temperature. The resistance of the precious metal coil increases with temperature, and this resistance change is nearly proportional to gas concentration. A bridge circuit within the sensor identifies resistance variations and converts them into voltage output signals to determine gas concentration. As the sensor responds to all combustible gases, it is unsuitable for identifying specific gas concentrations in complex combustible gas environments.

Due to its combustion principle, incomplete combustion at excessive gas concentrations can cause carbon deposition on the detection element, significantly reducing its precision and lifespan. Therefore, a protective mechanism should be implemented in external circuits: power supply to the sensor must be cut off when gas concentration reaches 100% LEL (Lower Explosive Limit) to prevent sensor damage.