| 摘要 |
PURPOSE:To detect a pressure difference with high precision by a piezoelectric oscillator which has a stable frequency by providing the piezoelectric oscillator in an airtight container and putting it opposite an electrode which receives pressure oscillation from a diaphragm. CONSTITUTION:The diaphragm 2 is provided on the top surface of the airtight container 1. The counter electrode 2a is provided on the reverse surface of the diaphragm 2 and the piezoelectric oscillator 3 is fitted by a holder 4 while a gap (t) is left. Further, electrodes 3a are provided on both surfaces of the piezoelectric oscillator 3. The diaphragm 2 is displaced when applied with pressure. Then, the gap (t) between the counter electrode 2a and piezoelectric oscillator 3 varies and the electrostatic capacity varies, so that the pressure difference is detected by an oscillation circuit. Further, the gap (t) is made adjustable. Therefore, the pressure is detected electrically from the variation (n) the gap between the diaphragm and piezoelectric oscillator, so the precision of the detection is improved; and the pressure is detected over a wide range by adjusting the gap. |
