| 摘要 |
<p>In a device in which a variation in air pressure produced by opening the closed door or window of a building is detected by a pressure sensor or microphone to produce an alarm signal, the detection sensitivity of the pressure sensor or microphone is improved. The detection sensitivity of the pressure sensor or microphone is greatly improved by maintaining the air pressure in the inner space of the building in such a manner that there is a difference between it and the air pressure in the outside of the building.</p> |
