Precision resistors: a review of the techniques of measurement, advantages, disadvantages, and results

The characteristics of the principal resistance measuring systems developed over the last two centuries are reviewed, Also reviewed is their application to measurement of resistance from /spl mu//spl Omega/ to M/spl Omega/. Included in the review are potentiometer systems and their adaptation to computer operation, the Wheatstone bridge, the enhanced Kelvin double-bridge and the current-comparator in both manual and computer operated forms. Methods of establishing ratio from the base 1 /spl Omega/ reference value throughout the range are discussed. Uncertainties attainable at the highest levels of precision are presented.