CALIBRATION OF CAPACITANCE STANDARDS WITH A QUADRATURE BRIDGE

摘要

National Metrology Institutes employ the quadrature bridge in the traceability chain to derive the farad from the ohm (represented with the quantum Hall effect). The bridge calibrates the capacitance product of the two capacitors being measured; a separate measurement with a ratio bridge is usually required to estimate each capacitor independently. We describe here a method which, by measuring three capacitance standards with the quadrature bridge only, permits to derive the value of each capacitor without resorting to other measurement systems. The method has been checked with an automated quadrature bridge at the level of 1 nF, and verified by measurement on a ratio bridge.