Resistance scaling up to 1 MΩ at PTB with a cryogenic current comparator

Abstract

A cryogenic current comparator (CCC) of the Delahaye type (1989) is used to scale the unit of resistance between 100 /spl Omega/ and 1 M/spl Omega/ in terms of R/sub K-90/. Measurements are demonstrated to check the accuracy and reproducibility of the system. Particularly for values above 10 k/spl Omega/ the uncertainty of measurement of the maintained standards can be reduced by more than one order of magnitude compared with conventional scaling methods.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>