| abstract |
A gas alarm device and a gas alarm method capable of driving a gas sensor with a limited battery capacity and securing a stable sensor sensitivity for a long period of time even under severe environmental conditions such as high humidity. I will provide a. A sensor drive circuit has a first pulse having a first cycle and a second pulse having a second cycle longer than the first cycle, and each of the first and second pulses is provided. A pulse drive signal having a high-level period for holding a high level, a low-level period for holding a low level, and a zero-level period for holding a zero level smaller than the low level, and a second pulse larger than the first pulse is generated. The gas sensor 1 is driven by the pulse drive signal, and the sensor detection circuit 9 detects the carbon monoxide gas concentration based on the output of the sensor element during the low level period of the pulse drive signal at every first cycle, and the alarm determination circuit 14 Determines whether the detected concentration of carbon monoxide gas has exceeded the alarm point, 1 reports an alarm indicating an abnormal carbon monoxide gas concentration when the carbon monoxide gas concentration exceeds an alarm point. |