A four-terminal-pair pulse-driven Josephson impedance bridge for 10 nF:10 nF capacitance ratio measurements

In this paper, the extension of PTB's pulse-driven Josephson impedance bridge to measure four terminal pair impedances is presented. First results for the ratio of two 10 nF capacitance standards will be shown. The difference between the ratio measured by the Josephson impedance bridge at 1233 Hz and the result from an impedance bridge based on inductive voltage dividers is 2 nF/F with a type-A uncertainty of 5 nF/F. Furthermore, the ratio results from this bridge at frequencies from 246 Hz to 4932 Hz are in good agreement with the results from a commercial precision capacitance bridge.