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Quartz thermometer

  • US 4,039,969 A
  • Filed: 01/02/1976
  • Issued: 08/02/1977
  • Est. Priority Date: 01/09/1975
  • Status: Expired due to Term
First Claim
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1. A quartz crystal thermometer comprising a single quartz element having at least a first and a second pair of electrodes and vibrating simultaneously in two different modes which are not mechanically coupled with each other and which correspond to two different frequencies of vibration, each of said first and second pairs of electrodes being arranged for providing high piezoelectric coupling with one corresponding mode of the said two modes of vibration and for providing no piezoelectric coupling with the other mode, one of the said two frequencies of vibration being a standard frequency and the other being dependent on the temperature of the quartz crystal, the thermometer further comprising a first and a second oscillator circuit respectively connected to the said first and second pairs of electrodes, and a frequency comparison device for comparing the oscillation frequencies of the first and second oscillator circuits and providing an output which is a measure of the detected temperature.

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