10-nF capacitance transfer standard

New dielectric capacitance standards with a nominal value of 10 nF, suitable to be employed in the reproduction of the farad unit starting from the quantum Hall resistance, have been constructed. The standards are based on commercial chip capacitance components encased in a thermostat, and are defined as four terminal-pair impedance standards. The capacitance value is within 50/spl middot/10/sup -6/ relative to nominal; dissipation factor is about 8 /spl middot/ 10/sup -5/ at 1 kHz. The relative temperature coefficient of the capacitance value versus external ambient temperature is expected to be /spl ap/1/spl middot/10/sup -8/ K/sup -1/ near 23 /spl deg/C.