AC and DC Quantized Hall Array Resistance Standards

Quantized Hall array resistance standards (QHARS) span values from $100\ \ \Omega$ to $1\ \ \mathrm{M} {\Omega}$ and demonstrate precision approaching that of single devices. This paper focuses on QHARS having values near $1\ \mathrm{k} {\Omega}$ for increased sensitivity using room-temperature direct current comparator (DCC) bridges and digital impedance bridges. We introduce a dc QHARS design that uses the Wheatstone bridge principle as a precise test of the QHARS self-consistency for dc measurements. Branched contacts and superconducting interconnections help to reduce ac and dc loading and leakage errors with near zero resistance at magnetic flux densities of 9 T.