Third generation of adapted wheatstone bridge for high resistance measurements at NIST

A third generation of adapted Wheatstone bridge is being developed at the National Institute of Standards and Technology (NIST) to improve high resistance measurements and scaling from 1 TΩ to 10 PΩ. Improvements to extend range and reduce uncertainties include: automated calibration of the voltage sources, modified bridge balancing algorithm, low-noise shielded cables, and software migration to a modern programming environment. Initial measurements agree well within the expanded uncertainties (k = 2) of the second generation NIST adapted Wheatstone bridge.