Quadrature Bridge for $R$– $C$ Comparisons Based on Polyphase Digital Synthesis

A milestone revision of the International System of Units (SI) was made at the 26th General Conference on Weights and Measures that four of the seven SI base units, i.e. kilogram, ampere, kelvin, and mole, are redefined by fundamental physical constants of nature. The SI base unit founding the electrical measurement activities, i.e. ampere, is defined by fixing the numerical value of the elementary charge to e = 1.602 176 634 × 10 −19 C. For electrical measurement, several major adjustments, mostly positive, are involved in this SI revision. In this paper, the main impacts of the new SI for electrical measurement activities are surveyed under the new framework.

Section: Realization Of Electrical Units a Previous Traceabilitymentioning

confidence: 99%

From μ ₀ to e: A Survey of Major Impacts for Electrical Measurements in Recent SI Revision

Wang

Zhao

et al. 2020

“…• A 5-channel source developed at INRIM and described in [6], [7], based on a commercial digital-to-analogue (DAC) board 2 and filter/buffer output stages, with fine trimming of the analog gain of each channel.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…According to the measurement functions (6) and 10, we considered the following uncertainty components:…”

Section: B Uncertainty Componentsmentioning

confidence: 99%

A Three-Arm Current Comparator Digitally Assisted Bridge for the Comparison of Arbitrary Four Terminal-Pair Impedances

Ortolano

D'Elia

Callegaro

2017

High accuracy impedance measurements are performed with coaxial transformer bridges, whose conventional design allow the comparison of like impedances-pure resistors or capacitors. Here we present a current comparator bridge suited for the measurement of impedances of arbitrary magnitudes and phase angles. The bridge has three arms, to connect the impedance under measurement and two calibrated standards. The bridge is digitally assisted and its operation is based on a polyphase digital sine wave synthesizer. To allow the measurement of mid-to low-impedance magnitudes, the bridge network and the balancing procedure are designed to approximate the four terminal-pair definition of the three impedance standards. The bridge has been extensively tested with conventional impedance standards and custom designed phase standards. The relative base accuracy is in the 10 −5-10 −6 range at kHz frequency. Index Terms-Impedance measurement, bridge circuits, electromagnetic devices, precision measurements. This activity has been partially funded by the Progetto Premiale MIUR-INRIM P6-2012, Implementation of the new International System (SI) of Units. The work has been carried out within the European Metrology Research Programme (EMRP) SIB 53, Automated impedance metrology extending the quantum toolbox on electricity. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

“…The implementation of the three-arm current comparator bridge here presented is derived from that of a two-arm digitally-assisted current comparator bridge [8], which showed good results in the comparison of like impedances. Digitally-assisted bridges [9][10][11][12][13][14] are based on the generation of the sine wave signals to be employed in the bridge with digital synthesized sources. This approach permits to simplify the bridge mesh and achieve automated operation.…”

Section: The Bridgementioning

confidence: 99%

“…The electromagnetic current comparator and the polyphase synthesized generator employed in the implementation are described in detail in [13,14]. The detector employed is a commercial Stanford Research mod.…”

Section: The Bridgementioning

confidence: 99%

A Three-Arm Current Comparator Bridge for Impedance Comparisons Over the Complex Plane

Callegaro

D'Elia

Ortolano

et al. 2015

We present here the concept of three-arm current comparator impedance bridge, which allows one to perform comparisons among three unlike impedances. Its purpose is the calibration of impedances having arbitrary phase angles against calibrated nearly pure impedances. An analysis of the bridge optimal setting and proper operation is presented. To test the concept, a two-terminal-pair digitally assisted bridge has been realized; preliminary measurements of an air-core inductor and of an RC network versus decadic resistance and capacitance standards, at kilohertz frequency, have been performed. The bridge measurements are compatible with previous knowledge of the standard values with relative deviations of parts in 10^{-5}