New realization of the ohm and farad using the NBS calculable capacitor

Results of a realization of the ohm and farad using the US National Bureau of Standards (NBS) calculable capacitor and associated apparatus are reported. The results show that both the NBS representation of the ohm and the NBS representation of the farad are changing with time, Omega /sub NBS/ at the rate of -0.054 p.p.m./year and F/sub NBS/ at the rate of 0.010 p.p.m./year. The realization of the ohm is of particular significance because of its role in assigning an SI value to the quantized Hall resistance. The estimated uncertainty of the ohm realization is 0.022 p.p.m. (1 sigma ), while the estimated uncertainty of the farad realization is 0.014 p.p.m. (1 sigma ).< >