PRESSURE MEASURING METHOD USING TUNING-FORK TYPE QUARTZ RESONATOR

摘要

PURPOSE:To make it possible to measure the accurate pressure without temperature errors by obtaining intrinsic resonance resistance (Z0 + Zt) at a temperature T. CONSTITUTION:A constant-voltage AC power supply is formed of a full-wave rectifier 3, a 1/10 attenuator 4, a comparator 5 and a voltage-controlled attenuator 6. The power supply is connected to a piezoelectric transducer 1. Thus a self-oscillating circuit is formed. The resonance current undergoes current to voltage conversion 2 and full-wave rectification 7. The signal corresponding to a resonance resistance Z is applied on one terminal of operating circuit 8. A resonance frequency (f) is applied on the other terminal of the circuit 8. In the operating circuit 8, the temperature T and the intrinsic resonance resistance (Z0 + Zt) for the resonance frequency (f) are obtained. Then, Z = Z - (Z0 + Zt) is operated. The pressure P of a gas corresponding to Z is obtained. Then, the errors due to the temperature at the piezoelectric transducer 1 can be eliminated.