Self-balancing resistance ratio bridge using a cryogenic current comparator

Abstract

A cryogenic current comparator resistance bridge, developed to measure the resistance ratios of 1, 10, 100, and 6453.2 Omega against 1 Omega , is described. It is shown that the precision of the 1- Omega comparison is better than 0.01 p.p.m. This is attained by using an improved feedback system in the secondary current source.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>