Improved technique and standard resistors for the measurement of high value resistances

A description is given of an adapted Wheatstone bridge measurement system based on the balanced-bridge method, which has been automated for the comparison of high-value resistance standards between 10/sup 8/ Omega and 10/sup 14/ Omega . The system has been tested with high-magnitude standard resistors. The relative measurement uncertainty of the system for the comparison of two 5*10/sup 8/- Omega resistors was found to be smaller than 1*10/sup -6/, which is about a factor of five better than values obtained with other systems. This value increases for bridge ratios of 1:10 and 1:100 at higher resistances to about 2*10/sup -5/.<
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