| 摘要 |
<p>A barometer comprises a frequency control circuit (5) connected to an input of a piezoelectric oscillator (6) whose AC resistance is indicative of the pressure to be measured, a current voltage converter (7) connected to receive the output of the piezoelectric oscillator, and a phase comparator (8) connected to receive the output of the frequency control circuit and to receive the output of the current voltage converter. A display device, such as a voltmeter (10) is connected to receive the output of the current voltage converter, which output is indicative of the pressure to be measured. The output of the phase comparator (8) is connected, for example, through a low pass filter (9) to the frequency control circuit.</p> |
