| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum gauge that measures pressures of a gas in wide range with one vacuum gauge. SOLUTION: Signals of frequencies corresponding to natural frequencies of vibrating bodies 24 and 28 that are output from initial vibration signal sources 41 and 42 are applied to vibration electrodes 29 and 30 so as to vibrate the vibrating bodies 24 and 28. The initial vibration signal sources 41 and 42 are used only for initial driving, and after the vibrating bodies 24 and 28 start vibration, switching circuits 39 and 40 are changed over. The phases of signals output from capacity voltage conversion circuits 33 and 34 are shifted by phase shift circuits 35 and 36, and they are applied to the vibration electrodes 29 and 30 through amplifiers 37 and 38, so as to keep resonant status. When the gains of the amplifiers 37 and 38 are adjusted so that the voltage of the driving signal to be applied to the vibrating electrodes 29 and 30 may be constant, the amplitudes of the vibrating bodies 24 and 28, i.e., the size of the signals output from the capacity voltage conversion circuits 33 and 34 changes corresponding to the Q value of the vibrating body. COPYRIGHT: (C)2010,JPO&INPIT |
