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A new current-comparator-based dual-channel calibration system for AC currents and AC voltages in the millivolt range has been developed. The range of generated currents is 1 mA–5 A, and the range of generated voltages is 1–500 mV. The calibration system in-phase and quadrature expanded measurement uncertainties ( $k=2$ ) are within 25\cdot 10^{\mathrm {\mathbf {-6}}} . Although the system has been developed primarily for operation at power frequencies, it is also capable of operating at frequencies up to 1000 Hz with slightly increased uncertainties. The traceability to SI units is established through the calibration of AC voltage by means of AC/DC transfer and DC voltage reference, standard resistor, capacitor, and current comparator ratios. [ABSTRACT FROM PUBLISHER]

An improved power standard derived from a current comparator power bridge for calibrating active/reactive power and energy meters under sinusoidal conditions is described. Measurements can be made at any power factor from zero lag through unity to zero lead, at positive or negative power, at 120 V, 5 A, and 50 or 60 Hz. The improved power standard has an estimated uncertainty of not more than 2.5 \mu\W/VA at k = 1. Special high-accuracy current and voltage range extenders have been incorporated to extend the current and voltage ranges up to 200 A and 1200 V, respectively. [ABSTRACT FROM PUBLISHER]

A modified technique for calibrating both the capacitance-ratio and dissipation-factor (DF) dials of a current-comparator-based high-voltage capacitance bridge has been developed at the Korea Research Institute of Standards and Science (KRISS). The capacitance-ratio and DF dials are calibrated in the ratio range from 1/1 to 1000/1 and in the DF range from 10 \times 10^-6 to 1 \times 10^-1 for both positive and negative polarities. From the calculated and measured values of the corresponding dial balanced readings, the errors in the capacitance-ratio- and DF-dial readings are derived. The relative uncertainty of the modified calibration technique is also obtained to be not more than 10 \times 10^-6 of unity for the ratio-dial calibration, whereas the relative uncertainty of the DF dials from 1 \times 10^-3 to 1 \times 10^-1 is not more than 0.4% of the dial indication except the dissipation lower than 1 \times 10^-3 for which the corresponding absolute uncertainty is 5 \times 10^-6. The comparison results of the calibration performed at KRISS and the National Research Council of Canada show a good consistency with the measurement uncertainty. [ABSTRACT FROM AUTHOR]

Abstract: The quantum Hall effect (QHE) discovery has revolutionized metrology by providing with a representation of the unit of resistance, , that can be reproduced within a relative uncertainty of one part in 109 and is theoretically only linked to Planckʼs constant h and the electron charge e. This breakthrough also results from the development of resistance comparison bridges using cryogenic current comparator (CCC). The QHE experimental know-how now allows the realization of perfectly quantized Quantum Hall Array Resistance Standards (QHARS) by combining a large number of single Hall bars. In the context of an evolution of the Système International (SI) of units by fixing some fundamental constants of physics, the determination of the von Klitzing constant through the use of the so-called Thompson–Lampard calculable capacitor and the realization of refined universality tests of the QHE are of prime importance. Finally, the fascinating graphene material might be a new turning point in resistance metrology. [Copyright &y& Elsevier]