A multifrequency quadrature bridge

A coaxial multifrequency quadrature bridge for linking capacitance and resistance standards has been realized. A precision ratio transformer having two cores and two secondary windings forms the fixed ratio arms of the bridge and two eight-decade two-stage inductive voltage dividers are used for the in-phase balancing. Most frequently, the bridge is used to calibrate 10 nF standard capacitors by comparing them with 12 906 /spl Omega/ or 10000 /spl Omega/ reference resistors. The calibration uncertainty (k=2) is less than 1 part in 10/sup 5/ in a frequency range from 400 Hz to 5 kHz. After being calibrated by means of the quadrature bridge, the 10 nF capacitors serve as reference standards for calibration of capacitors of lower values.