Analysis of a dual-balance high-resistance bridge at 10 T/spl Omega/

The NIST guarded active-arm bridge, using a third DC source and a second detector to balance the guard network, is described. Improvements to the NIST active-arm bridge and the design and construction of improved high resistance standards have facilitated the extension of NIST calibration services to the 10 T/spl Omega/ decade of resistance. The 10 T/spl Omega/ calibration service has been offered as a special test for NIST customers; the 100 T/spl Omega/ special test will be available later this year. To ensure the quality of the measurements provided to the customer and to evaluate the bridge, many verifications including the use of check standards, redundant measurement systems, and multiple bridge ratios have been used. Analysis techniques described for the 10 T/spl Omega/ decade of resistance can also be applied to the 100 T/spl Omega/ decade of resistance.