Precision high-value resistance scaling with a two-terminal cryogenic current comparator
Randolph E. Elmquist, George R. Jones, Felipe L. Hernandez-Marquez, Marcos Bierzychudek
We describe a cryogenic two-terminal high-resistance bridge and its application in precision resistance scaling from the quantized Hall resistance (QHR) at RH = RK/2 = 12 906.4035 _ to decade resistance standards with values between 1 M_ and 1 G_. The design minimizes lead resistance errors with multiterminal connections to the QHR device. A single variable voltage source and resistive ratio windings are utilized to achieve excellent dynamic stability, which is not readily obtained in low-current measurements with conventional cryogenic current comparators (CCCs). Prototypes of his bridge have been verified by a successful international comparison of high-resistance scaling using two-terminal CCCs in the national metrology institutes of Argentina, Mexico, and the United States.