Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Uncertainty of the Ohm Using Cryogenic and Non-Cryogenic Bridges



Alireza Panna, Marlin E. Kraft, Albert Rigosi, George R. Jones Jr., Shamith Payagala, Mattias Kruskopf, Dean G. Jarrett, Randolph Elmquist


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.
Proceedings Title
CPEM 2018 Conference Digest
Conference Dates
July 8-13, 2018
Conference Location
Paris, FR
Conference Title
Conference on Precision Electromagnetic Measurements (CPEM) 2018


quantized Hall resistance, traceability, cryogenic current comparator, direct current comparator, standard resistor


Panna, A. , Kraft, M. , Rigosi, A. , Jones Jr., G. , Payagala, S. , Kruskopf, M. , Jarrett, D. and Elmquist, R. (2018), Uncertainty of the Ohm Using Cryogenic and Non-Cryogenic Bridges, CPEM 2018 Conference Digest, Paris, FR, [online], (Accessed April 19, 2024)
Created July 8, 2018, Updated April 19, 2022