Circuit for determining the effective series resistance and Q-factor of capacitors
Patent 4777430 Issued on October 11, 1988. Estimated Expiration Date: 
March 16, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 16, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3034044 3626285 3631336 3840805 Direct reading reactance meter Impedance/admittance measuring circuit Reactance meter Patent #: 4419623 InventorAssigneeApplicationNo. 07/026264 filed on 03/16/1987US Classes:324/659, With loss characteristic evaluation324/653, For figure of merit or Q value330/79By transformer feedbackExaminersPrimary: Eisenzopf, Reinhard J.Assistant: Harvey, Jack B. Attorney, Agent or FirmInternational ClassesG01R 27/26 (20060101)G01R 27/02 (20060101) G01R 31/01 (20060101) AbstractA meter circuit for measuring the effective series resistance (ESR) and Q-Factor of a capacitive device has an operational amplifier with an input to which a source of AC input voltage is applied. A feedback circuit is connected between output and input of the amplifier. A series network is connected between the feedback circuit and ground. This network has an inductor of known Q-Factor in series with a capacitive device whose Q-factor is to be determined. Voltmeters measure the applied input voltage and output voltage of the amplifier. Where the series resistances of the inductor and capacitive device at resonance frequency have a low total magnitude, the meter circuit can be modified by inserting a wideband transformer, having very low output impedance, in the feedback circuit in series with an adjustable gain operational amplifier. | |
