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A measurement setup is developed for the accurate ratio measurement of ac current transformers (CTs) for primary currents up to 5 kA. A unique property of the system is the use of high-quality digitizers for sampling of the secondary current signals and step-down transformers with different current ratios. This allows for accurate comparison of CTs even when their nominal ratios are not equal. The calibration results of the key components in the setup show that the sampling current ratio bridge has a ratio uncertainty of better than 2 \muA/A in magnitude and 0.8 \murad in phase for CT-under-test current ratios that do not differ by more than a factor of 5 from one of the ratios in the reference CT. The linearity of the bridge for input currents changing between 1% and 120% of nominal input current is better than 4 \muA/A in magnitude and 0.5 \murad in phase. [ABSTRACT FROM PUBLISHER]

This paper describes a power measurement setup that is able to measure power up to the MHz region. The setup consists of a commercial digitizer together with a switch unit, and buffer amplifiers to alternately measure the voltage and current channel. A reference AC voltmeter provides an absolute reference by simultaneous measurement of the rms voltage of one channel, which significantly reduces the need for flat frequency response of the setup. The method described in this paper makes complex voltage ratio measurements possible in the range of 50 Hz up to 1 MHz with an uncertainty of a few parts in 10^6 and in addition can be applied in wideband power measurements. Using our new method, the frequency response of cables and several other components is no longer a limiting factor for power measurements up to 1 MHz. [ABSTRACT FROM PUBLISHER]

We describe measurements with a pulse-driven Josephson arbitrary waveform synthesizer (JAWS) that uses a ternary arbitrary bit-stream generator as the bias source. This system is designed to be used as an ac Josephson voltage standard. From these measurements, we conclude that the system is operational for root-mean-square voltages of up to 220 mV. We measured the operating margins for different voltages synthesized with different numbers of junctions, waveforms, and bias conditions. We also present results on the influence of the critical current on the operating margins. [ABSTRACT FROM AUTHOR]

We have developed a home-built vibrating reed (VR) electrometer. The heart of the meter is a VR capacitor, which excels in a stable and low input leakage current of only 8 aA with a 2 aA noise for a 1 h measurement. This paper demonstrates that this makes the instrument ideal for the characterization of subtle charge effects in, for example, connectors and cables. The exceptional sensitivity of the electrometer is proven in a measurement of the leakage resistance of an air gap capacitor which results in a value of Rleak = (8.8 ± 0.3) · 1017 Ω, obtained at a test voltage of only 10 V. Calibration of the system with both a picoampere and a picocoulomb generator shows that the instrument has an accuracy of 15 parts in 106 (k = 1) at a current of 1 pA. As far as we are aware, this is the best uncertainty for a room temperature electrometer published so far. [ABSTRACT FROM AUTHOR]

A high accuracy current source has been developed for the generation of very small currents (below 200 pA) based on applying a linear voltage ramp to a capacitor. Using software-controlled compensation for the nonlinearity of the voltage ramp, a stable current can be reached within a few seconds. A voltage ramp within typically 10.10-6 of any desired value between less than 1 mV/s and several hundreds of mV/s can be realized. Using a high quality air-dielectric capacitor, currents below 200 pA can be generated With an uncertainty of 20 μA/A (k = 2), with a lower limit 0f 2.0 aA (k=2). [ABSTRACT FROM AUTHOR]

Presents a study that exploited two complementary single electron tunneling devices for use in electrical current metrology. Set current source; Current steps for the R-pump with smaller junctions for different frequencies and series resistances; Summary and conclusion.