The sensor of MPS combustible gas sensor is a micro-machined film with embedded Joule heater and resistance thermometer. MEMS sensor is mounted on PCB and packaged in a sturdy enclosure open to ambient air. The presence of flammable gas will change the thermodynamic characteristics of the air/gas mixture measured by the sensor. The sensor data is processed by the patent-pending algorithm to report the accurate concentration and classify flammable gases.