Back to results
US 4,528,498 AGranted
Frequency compensating current circuit for a current comparator capacitance bridge
OwnerEddy Soinventor
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
OwnerEddy Soinventor
Estimating the term…
A method and apparatus for rendering a high-voltage current-comparator capacitance bridge insensitive to frequency fluctuations when used for measuring inductance. A compensating current, proportional to twice the change in the current through the reference capacitor due to frequency fluctuations, is driven into the first comparator winding through which the current from the reference capacitor passes, resulting in a current in that winding having frequency characteristics similar to those of the current passing through the second winding which is connected to the inductance. This compensating current is derived from a reduced replica of the applied high-voltage by deriving a voltage signal which is a function of the frequency fluctuation, producing an amplitude controlled reduced replica voltage using the frequency fluctuation voltage and converting the amplitude controlled voltage to the compensating current for the first comparator winding.
In a current comparator capacitance bridge for measuring inductance wherein the bridge includes first comparator winding means connected to a reference capacitor, second comparator winding means for connection to the inductance, and a comparator amplifier connected to the first comparator winding for providing a reduced replica of a voltage applied to the bridge, a compensating current circuit for rendering the bridge insensitive to frequency fluctuations comprising:
Dependencies are inferred from the claim text.