We describe recent scaling measurements to decade resistance levels based on both cryogenic and non-cryogenic current comparator bridges. National measurement institutes and the International Bureau of Weights and Measures derive traceability for the SI ohm using the quantum Hall effect, with the primary comparisons made at the resistance value RK-90/2 = 12906.4035 Ω. Cryogenic current comparator scaling methods are preferred since large resistance ratios of 100 or more are achieved with unsurpassed uncertainty. The quantized Hall resistance standard based on graphene soon could allow less complex and more cost-effective room-temperature resistance bridges to provide SI traceability. Estimates of the relative uncertainties of the possible scaling methods will be provided in this report, along with a discussion of the advantages of several scaling paths.
CPEM 2018 Conference Digest
July 8-13, 2018
Conference on Precision Electromagnetic Measurements (CPEM) 2018
quantized Hall resistance, traceability, cryogenic current comparator, direct current comparator, standard resistor