| 摘要 |
PROBLEM TO BE SOLVED: To provide a physical/chemical quantity measuring device using a crystal oscillator, which can be used readily in making a plurality of devices operate simultaneously, to improve the detection accuracy by suppressing the influence of disturbance, and to make its circuit configuration very simple. SOLUTION: A ring circuit is formed as an oscillation circuit A1, by serially connecting a first capacitor C1, a second capacitor C2, a resistance element R3 and the crystal oscillator X1, in this order, in a ring-like fashion; a connecting wire between the crystal oscillator X1 and the resistance element R3 is connected to a circuit common, and a connecting wire between the resistance element R2 and the second capacitor C2 is connected to one input terminal of a differential amplifier A1; a connecting wire between the crystal oscillator X1 and the first capacitor C1 is connected to the other input terminal of the differential amplifier A2; and a connecting wire between the first capacitor C1 and the second capacitor C2 is connected to the output terminal of the differential amplifier A1. COPYRIGHT: (C)2009,JPO&INPIT
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