A precise measurement of QHR in NIM

Equipment for the precise measurement of quantized Hall resistance (QHR) is described. The essential components of this equipment are a resistance comparator of one to one ratio with a comparison uncertainty of 3*10/sup -8/ and two specially designed resistor networks for determination of the ratio between 12906.4 Omega of QHR at i=2 and 10 k Omega or 1 k Omega . The transfer procedure from QHR to 10 k Omega can be completed easily with this equipment by a few steps of one-to-one comparison, with a total uncertainty of 5*10/sup -8/.<
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