Characterization of 1-10 000 nF capacitance standard for future CCEM key comparison

The transportable capacitance standard 1 nF-10 /spl mu/F for CCEM key comparison of capacitance is developed. The standard consists of five ceramic dielectric hermetically sealed capacitors with 4 terminal-pair connections. Capacitors are placed into temperature-controlled oven, which maintains a constant (/spl plusmn/0,05/spl deg/C) temperature of about 30/spl deg/C. The long-term measurements have shown that capacitance stability is within the limits of 1-10 ppm per one year, short-term stability is of order of few units of 10/sup -8/.