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The S-matrix method for high-frequency calibration of capacitors: numerical uncertainty evaluation
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Fundamentals of Measurement: Small Electric Currents
Full text linkThe values of electrical quantities span over an incredibly wide range. In the same laboratory, one can manage the measurement of, say, both small 1 pF capacitors and of 1000 F supercaps for energy storage. Conductors ask for measurement of resistances in the milliohm; insulator resistance can go up to several teraohm. A range of 15 orders of magnitude seems normal - until one considers that the same range for a length measurement, for example, would go from the size of a bacterium to a journey to the moon. Technological development pushes the need for accurate measurements of electrical quantities at the extremes of these ranges
A quantum ampere
Full text linkThe revision of the International System of Units (SI), implemented since 20 May 2019, has redefined the unit of electric current, the ampere ( A), linking it to a fixed value of the elementary charge. This paper discusses the new definition and the realisation of the electrical units by quantum electrical metrology standards, which every year become more and more accessible, reliable and user friendly
Traceable measurement of electrical impedance
Full text linkScientists and engineers from different backgrounds share the need for measurement of electrical impedance and related quantities. Equivalent lumped resistance, capacitance, or inductance are common parameters in the characterization, specification, and design of electrical and electronic components. Electric and magnetic material properties such as resistivity, permittivity, and permeability are derived from impedance and from geometrical measurements. Many sensors of physical quantities have impedance as their output quantity. The basis of electrochemical impedance spectroscopy (EIS) and electrical impedance tomography (EIT) is impedance measurement. As in all measurements, the basis of accurate impedance measurements is: ·a proper definition of the measurand; and · a traceability to the impedance units of the International System (SI), achieved through the use of calibrated impedance meters and impedance standards
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