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Bridged capacitor sensor measurement circuit

  • US 20030155936A1
  • Filed: 02/15/2002
  • Published: 08/21/2003
  • Est. Priority Date: 02/15/2002
  • Status: Active Grant
First Claim
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1. Apparatus for measuring a process variable comprising:

  • a first sensing capacitor having a capacitance, C1, based on the process variable;

    a second sensing capacitor having a capacitance, C2, based on the process variable;

    a bridge node coupling a first side of the first sensing capacitor to a first side of the second sensing capacitor;

    an excitation source supplying at least first and second voltage levels; and

    a switch circuit selectively coupling a second side of each of the first and second sensing capacitors to the excitation source to derive a representation of C1-C2 at the bridge node.

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