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Capacitive measurement system

  • US 4,426,616 A
  • Filed: 10/06/1981
  • Issued: 01/17/1984
  • Est. Priority Date: 10/06/1981
  • Status: Expired due to Term
First Claim
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1. A system for measuring the capacitance C of a capacitor independently of the resistance R of a resistor connected in parallel with said capacitor, which comprises:

  • a first source of alternating sinusoidal voltage of a first frequency W0 ;

    a second source of alternating sinusoidal voltage of a different second frequency W1 ;

    switch means for alternatively connecting said capacitor and parallel resistor to said first and second sources during successive intervals;

    current measurement means for providing average values of current supplied to said capacitor and parallel resistor, said current measurement means providing an average current value N0 during an interval with said capacitor and parallel resistor is connected to said first source and providing an average current value N1 during an interval when said capacitor and parallel resistor are connected to said second source; and

    computer means for calculating said capacitance in accordance with an equation ##EQU8## where K0 is a multiplier constant for converting the current value N0 to an admittance value (W0 C)2 +1/R2, and K1 is a multiplier constant for converting the current value N1 to an admittance value (W1 C)2 +1/R2.

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