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Dielectric constant detecting apparatus

  • US 5,414,368 A
  • Filed: 09/10/1992
  • Issued: 05/09/1995
  • Est. Priority Date: 09/10/1991
  • Status: Expired due to Fees
First Claim
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1. An apparatus for detecting a dielectric constant of liquid, said apparatus comprising:

  • phase shifting means for creating a shifted high frequency voltage signal by shifting a phase of an unshifted high frequency voltage signal by an amount corresponding to said dielectric constant of said liquid;

    applying means for applying said unshifted high frequency voltage signal to said phase shifting means;

    a resistor having a first end and a second end, wherein said first end of said resistor is connected to said phase shifting means and said second end of said resistor is connected to said applying means;

    detecting means connected across said resistor for detecting a phase shift between said shifted high frequency voltage signal created by said phase shifting means and said unshifted high frequency voltage signal applied from said applying means;

    control means for adjusting said unshifted high frequency voltage signal from said applying means to adjust said phase shift detected by said detecting means toward a predetermined phase shift value,wherein said dielectric constant of said liquid is represented by at least one of a first dielectric signal produced by said control means which is based on said phase shift detected by said detecting means and a second dielectric signal produced by said applying means which is based on said adjusted unshifted high frequency voltage signal; and

    an insulator for integrally covering said phase shifting means, said resistor and at least one part of said detecting means.

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