A multifrequency quadrature bridge for realization of the capacitance standard at ETL

摘要

A quadrature bridge which will be used in the chain of measurements from the QHR to the standard of capacitance at ETL has been developed. The bridge may be balanced at several frequencies including the conventional 10/2/spl pi/ kHz (i.e., /spl omega/=10/sup 4/ rad/s). At its present stage of development the bridge achieves a relative standard uncertainty of 2/spl times/10/sup -7/ in comparing 1 nF capacitors and 100 k/spl Omega/ resistors at frequencies from 3/8/spl times/10/2/spl pi/ kHz to 10/2/spl pi/ kHz. With further development it is expected that a relative standard uncertainty of about 5/spl times/10/sup -8/ will be achieved.