Resistance Standards Research Articles

Impedance Metrology: Bridging the LF–RF Gap

This article describes two approaches for modeling impedances along the physical gap existing between the low- and high-frequency ranges. For this purpose, the physics of a Haddad-type resistor standard has been investigated taking into account the EM-field propagation and the effect of connectors. It turns out that above 30 MHz, the frequency dependence of the resistance is mainly dominated by the effects of the connector system. In addition, a new capacitor standard has been designed by means of physical simulations. In both approaches, a new method to exploit the information of the impedance matrix is presented. The use of this method considerably improves the impedance model. Preliminary results show a good agreement with measured data at low and high frequencies. A first estimation of the uncertainty has been also included in this article.

Calibration of ultrastable low-noise current amplifiers without direct use of a cryogenic current comparator

The established calibration of the transresistance of the ultrastable low-noise current amplifier (ULCA) directly involves a cryogenic current comparator (CCC). Here, we present an alternative approach based on a calibrated set of three resistors and three digital voltmeters. This approach was experimentally verified for a two-channel ULCA with nominally 1 GΩ transresistance using PTB’s travelling 12 bit CCC setup in an on-site comparison at METAS. Series of interleaved experiments included calibrations of the input and output stages of two different ULCA channels. The consistency found between the conventional calibration with PTB’s CCC and calibration with METAS’ set of three resistors—each traced to the quantum Hall resistance with METAS’ CCC—confirms that the alternative traceability chain provides valuable results. If the standard resistors are calibrated without using a CCC, the new method even opens the possibility to calibrate the ULCA without any CCC in the traceability chain involved, however, typically at the expense of increased uncertainty.

Comparison between Graphene and GaAs Quantized Hall Devices with a Dual Probe.

A graphene quantized Hall resistance (QHR) device fabricated at the National Institute of Standards and Technology (NIST) was measured alongside a GaAs QHR device fabricated by the National Research Council of Canada (NRC) by comparing them to a 1 kΩ standard resistor using a cryogenic current comparator. The two devices were mounted in a custom developed dual probe that was then assessed for its viability as a suitable apparatus for precision measurements. The charge carrier density of the graphene device exhibited controllable tunability when annealed after Cr(CO)3 functionalization. These initial measurement results suggest that making resistance comparisons is possible with a single probe wired for two types of quantum standards - GaAs, the established material, and graphene, the newer material that may promote the development of more user-friendly equipment.

The next generation of current measurement for ionization chambers

Re-entrant ionization chambers (ICs) are essential to radionuclide metrology and nuclear medicine for maintaining standards and measuring half-lives. The requirements of top-level metrology demand that systems must be precise and stable to 0.1 % over many years, and linear from 10−14 A to 10−8 A. Thus, laboratories depend on bespoke current measurement systems and often rely on sealed sources to generate reference currents. To maintain and improve present capabilities, metrologists need to overcome two looming challenges: ageing electronics and decreasing availability of sealed sources. Possible solutions using Ultrastable Low-Noise Current Amplifiers (ULCAs), resistive-feedback electrometers, and (quantum) single-electron pumps are reviewed. Broader discussions of IC design and methodology are discussed. ULCAs show promise and resistive-feedback systems which take advantage of standard resistor calibrations offer an alternative.

Advanced Temperature-Control Chamber for Resistance Standards

Calibration services for resistance metrology have continued to advance their capabilities and establish new and improved methods for maintaining standard resistors. Despite the high quality of these methods, there still exist inherent limitations to the number of simultaneous, measurable resistors and the temperature stability of their air environment. In that context, we report progress on the design, development, and initial testing of a precise temperature-control chamber for standard resistors that can provide a constant-temperature environment with a stability of ± 6 m°C. Achieving this stability involved customizing the chamber design based on air-flow simulations. Moreover, microprocessor programming allowed the air flow to be optimized within an unsealed chamber configuration to reduce chamber temperature recovery times. Further tests were conducted to improve the stability of the control system and the efficiency of the chamber.

Design and development of instrumentation for the measurement of sensor array responses.

Indigenous instrumentation has been designed and developed for the measurement of the concentration of analytes from eight conductometric metal oxide sensors. The hardware scheme of instrumentation is based on the astable multivibrator configuration. The hardware measures the resistance output from the sensors, conditions, processes, and displays the data on the liquid crystal display. An 8051 based processor averages the data, converts them into engineering units, and sends them to remote PC through ethernet communication for post-data analysis. A graphical user interface (GUI) is developed to acquire, monitor, and display the eight channels' sensor output. GUI plots the online data and offline data as a popup window. The hardware and software of the instrument were tested with standard resistors for calibration and found that in-house developed instrumentation is able to measure with an accuracy of ±0.5% with a resolution of 500 Ω. The instrument has been tested with a semiconductor metal oxide sensor, viz., chromium niobate (CrNbO4).

Implementation of a graphene quantum Hall Kelvin bridge-on-a-chip for resistance calibrations

The unique properties of the quantum Hall effect allow one to revisit traditional measurement circuits with a new flavour. In this paper we present the first realization of a quantum Hall Kelvin bridge for the calibration of standard resistors directly against the quantum Hall resistance. The bridge design is particularly simple and requires a minimal number of instruments. The implementation here proposed is based on the bridge-on-a-chip, an integrated circuit composed of three graphene quantum Hall elements and superconducting wiring. The accuracy achieved in the calibration of a 12 906 standard resistor is of a few parts in 108, at present mainly limited by the prototype device and the interferences in the current implementation, with the potential to achieve few parts in 109, which is the level of the systematic uncertainty of the quantum Hall Kelvin bridge itself.

Theories and applications of electrical quantum benchmarks

The voltage unit and the resistance unit are the basic units in electrical metering. The Josephson voltage standard and the quantized Hall resistance standard have replaced the physical reference that was maintained by standard batteries and standard resistors. This paper investigates the working principle of voltage quantum reference, resistance quantum reference and current quantum reference. Furthermore, the applications of these new electrical References are discussed. This study provides theoretical support for the development of electricity value transfer methods.

DETERMINATION OF THE STANDARD RESISTOR TEMPERATURE COEFFICIENTS AND THEIR UNCERTAINTIES

<p>SNSU TK-BSN’s capability in determining the temperature coefficients of a standard resistor has been improved. The temperature coefficient is one of the important parameter in determining the definition of the standard resistor. Currently, the measurement result has been reported together with the measurement uncertainty. The determination itself is based on a numerical approach of Taylor Series Approximation (TSA) instead of based on a fitting to a certain equation. And by this determination, the uncertainty was calculated. The determination was validated by comparing the measurement result committed by SNSU TK-BSN to that of by the manufacturer. The equation for the temperature coefficient follows the parabolic equation with an alpha coefficient of -5.30 x 10-8 Ω/Ω/°C and beta coefficient of -4.70 x 10-8 Ω/Ω/°C<sup>2</sup>, with the respective uncertainties of 2.4 x 10-8 Ω/Ω/°C and 1.6x 10-8 Ω/Ω/°C<sup>2</sup>, respectively. SNSU TK-BSN measurement results in determining the temperature coefficient in agreement with the manufacturer's measurement results show an appropriate value. This correspondence has an equivalent degree of 0.20 for the alpha temperature coefficient and 0.27 for the beta coefficient.</p>

Investigation of not fully stable fluids by the method of controlled pulse heating. 4. Evaluation of PMMA thermophysical properties up to 673 K

It has been shown that it is possible, in principle, to evaluate a set of the thermophysical properties of a polymer using a single high-power heating pulse over a wide temperature range including the region of states superheated with respect to the temperature of thermal decomposition onset in a quasi-static process. The corresponding research tool consists of the experimental method of controlled pulse heating of a fast-response wire probe with a characteristic measurement time of 10−3 s combined with a numerical method for assessing the temperature dependencies of the thermophysical properties from the experimental thermal response to the heat pulse. The evolution of the probe temperature at a given heating power was derived on the basis of primary data; namely, voltage drops on the probe and standard resistor in the course of heat release. A numerical procedure based on the model of optimising the heat conduction parameters has been constructed using genetic algorithms. The most probable temperature dependencies of the thermal conductivity and volumetric heat capacity for a polymethyl methacrylate (PMMA) sample have been determined in the range 300–673 K.

Modeling and state of health estimation of nickel–metal hydride battery using an EPSO-based fuzzy c-regression model

The prognostic and health management of the batteries continued to attract interest from automobile manufacturers as the key for lowering life-cycle costs, reducing unexpected power outages, and one of the most important and efficient ways for energy storage for electric vehicle applications. Indeed, an effective battery health monitoring depends on accurate estimation of state of health (SOH). However, the SOH cannot be directly measured by sensors in the battery management system. Moreover, the SOH estimation based on a standard resistor–capacitor (RC) battery model is not so accurate because a RC model is obtained with some approximations and without taking into account more detailed knowledge about the chemical reactions happening inside the battery. In this paper, a combined battery modeling and SOH estimation method over the lifespan of a nickel–metal hydride (Ni–MH) battery is proposed. First, a fuzzy c-regression model based on Euclidean particle swarm optimization is applied to modeling a Ni–MH battery. Second, the SOH monitoring is determined according to the discharge rate of the battery model. The performance of the proposed method has been analyzed through the modeling and the estimation of the SOH using a real data set of the Ni–MH battery.

Comparison between NIST Graphene and AIST GaAs Quantized Hall Devices.

Several graphene quantized Hall resistance (QHR) devices manufactured at the National Institute of Standards and Technology (NIST) were compared to GaAs QHR devices and a 100 Ω standard resistor at the National Institute for Advanced Industrial Science and Technology (AIST). Measurements of the 100 Ω resistor with the graphene QHR devices agreed within 5 nΩ/Ω of the values for the 100 Ω resistor obtained through GaAs measurements. The electron density of the graphene devices was adjusted at AIST to restore device properties such that operation was possible at low magnetic flux densities of 4 T to 6 T. This adjustment was accomplished with a functionalization method utilized at NIST, allowing for consistent tunability of the graphene QHR devices with simple annealing. Such a method replaces older and less predictable methods for adjusting graphene for metrological suitability. The milestone results demonstrate the ease with which graphene can be used to make resistance comparison measurements among many National Metrology Institutes.

Reliability of printed power resistor with thick-film copper terminals

This paper is focused on the thick-film power resistors with copper terminals. These terminals are created by the new Thick Printed Copper (TPC) technology. This technology is based on sequential screen printing and firing of copper paste in nitrogen atmosphere on an alumina substrate. Thick-film power resistor with copper terminals represents a potential replacement of standard wirewound power resistors and allows the direct integration of resistors on TPC substrates. Printed resistors on TPC substrates can be supplemented with discrete electronic components which creates the possibility to realize really complex power electronic circuits. The direct integration of printed components is not possible in case of using the standard Direct Bonded Copper (DBC) technology. The main benefits of printed resistors based on TPC technology are their low thickness and good thermal conductivity. The low thickness of resistors is important for miniaturization of final electronic devices. The resistor main electrical parameters as the temperature coefficient of resistance, temperature coefficient and nominal resistance value after dry heat aging and after thermal cycling, insulation resistance, dielectric strength etc., are described in this paper.

Characterization of $1~\mathrm{k}\Omega$ Metal-Foil Standard Resistors and Continuing Drift-Rate Evaluation of 1$\Omega$ and $10~\Omega$ Standard Resistors

A set of standard resistors is a key component of resistance calibration. We have been developing a series of compact superstable standard resistors that meet calibration laboratory demands. In this paper, we describe manufacturing and evaluation of ${1}~{\mathrm {k}\Omega }$ standard resistors. All the resistors elements are made with the “stress free bulk metal foil” technology. We found that all standard resistors show extremely small average drift rates, e.g., smaller than ${10~\mathrm {n}\Omega /(\Omega ~\mathrm {year})}$ and small temperature coefficients typically around $35~{{n}\Omega /(\Omega \, {}^\circ \mathrm {C})}$ at 23 °C. Moreover, continuing the evaluation of drift behavior of $ {1}~{\Omega }$ and $ {10}~{\Omega }$ standard resistors is discussed.

Role of Quasiparticles in an Electric Circuit with Josephson Junctions.

Although Josephson junctions can be viewed as highly nonlinear impedances for superconducting quantum technologies, they also possess internal dynamics that may strongly affect their behavior. Here, we construct a computational framework that includes a microscopic description of the junction (full fledged treatment of both the superconducting condensate and the quasiparticles) in the presence of a surrounding electrical circuit. Our approach generalizes the standard resistor capacitor Josephson model to arbitrary junctions (including, e.g., multiterminal geometries and/or junctions that embed topological or magnetic elements) and arbitrary electric circuits treated at the classical level. By treating the superconducting condensate and quasiparticles on equal footings, we capture nonequilibrium phenomena such as multiple Andreev reflection. We show that the interplay between the quasiparticle dynamics and the electrical environment leads to the emergence of new phenomena. In a RC circuit connected to single channel Josephson junction, we find out-of-equilibrium current-phase relations that are strongly distorted with respect to the (almost sinusoidal) equilibrium one, revealing the presence of the high harmonic ac Josephson effect. In an RLC circuit connected to a junction, we find that the shape of the resonance is strongly modified by the quasiparticle dynamics: close to resonance, the current can be smaller than without the resonator. Our approach provides a route for the quantitative modeling of superconducting-based circuits.

Quantum Hall devices for the primary resistance standard based on the GaAs/AlxGa1−x As heterostructure

Quantum Hall devices for primary resistance metrology based on the GaAs/Al[Formula: see text]Ga[Formula: see text]As heterostructure were fabricated and compared with the devices from international metrology organization International Bureau of Weights and Measures (BIPM) by calibrating the same 100 [Formula: see text] transfer standard resistor with a cryogenic current comparator. Relative deviation between NIM-made device NIM-C1 and BIPM-made device BIPM-1 was −4.49 parts in 109 with an uncertainty of 3.63 parts in 109 which indicated NIM-C1 satisfied the requirement for the primary resistance standard.

Pressure and Temperature Dependence of Field-Induced Oscillation in Two-Terminal Device Based on Vanadium Dioxide Thin Film

In this paper, we investigated the pressure and temperature dependence of the frequency and amplitude of the field-induced oscillation created in a two-terminal device based on a vanadium dioxide (VO₂) thin film. First, a simple oscillation circuit was constructed using a VO₂-based two-terminal device, a standard resistor, and a DC power supply. Then, the frequency and amplitude variation of the field-induced oscillation was observed for pressure changes applied to the VO₂ device in a pressure chamber. This variation of the oscillation characteristics was also examined for ambient temperature changes applied to the VO₂ device using a plate heater. When the chamber pressure increased from 0 to 5 MPa with a step of 1 MPa at 25 °C, the oscillation frequency increased from ~592 to ~739 kHz, and the oscillation amplitude decreased from ~12.60 to ~11.40 V. Similarly, when the heater temperature increased from 25 to 50 °C (step: 5 °C) without applied pressure, the oscillation frequency increased from ~592 to ~819 kHz, and the oscillation amplitude decreased from ~12.60 to ~7.16 V. Owing to linear pressure and temperature responses of the VO₂ oscillation, the pressure and temperature sensitivities of the oscillation frequency and amplitude could be obtained as four different constant coefficients from the measurement results. These coefficients can be directly utilized for simultaneously measuring pressure and temperature variation applied to the VO₂ device, which can be beneficially applied to localized temperature and pressure sensing at a very small area less than 1 mm².

고온 시효 시험에 따른 Epoxy 솔더 접합부의 접합 특성 평가

Bonding properties of epoxy-containing solder joints were investigated by a high temperature aging test. Specimens were prepared by bonding an R3216 standard chip resistor to an OSP-finished PCB by a reflow process with two basic types of solder (SAC305 & Sn58Bi) pastes and two epoxy-solder (SAC305+epoxy & Sn58Bi+epoxy) pastes. In all epoxy solder joints, an epoxy fillet was formed in the hardened epoxy, lying around the outer edge of the solder joint, between the chip and the Cu pad. In order to analyze the bonding characteristics of solder joints at high temperatures, a high-temperature aging test at 150°C was carried out for 14 days (336 h). After aging, the intermetallic compound Cu6Sn5 was found to have formed in the solder joint on the Cu pad, and the shear stress on the conventional solder joint was reduced by a significant amount. The reason that the shear force did not decrease much, even though in epoxy solder, was thatbecause epoxy hardened at the outer edge of the supported solder joints. Using epoxy solder, strong bonding behavior can be ensured due to this resistance to shear force，even in metallurgical changes such as those where intermetallic compounds form at solder joints.

Composite milliohm-meter for resistance measurement of precision current shunts in industrial environment

A composite milliohm-meter (Com-mOhm), based on standard four-wire Kelvin resistance measurement method, was developed for measurements of precision current shunts used in an industrial environment. The system is comprised of a precision, temperature compensated, low drift, high stability 100 mA current source and a 4 ? digit commercial multimeter. Due to the set of specific demands and conditions concerning the industrial applications of precision current shunts, standard measurement equipment and methods could not be implemented. The composite resistor standard was used for temperature stabilization of the precision current source based on precision voltage reference REF102. The measurement precision of ?0.1 milliohms is observed during measurement of 20 milliohm current shunts.

Validation of a high resistance calibration method based on a binary voltage divider

A method to measure standard resistors in the range 10 kΩ to 1 TΩ, based in automated bridge using a binary voltage divider is described, tested and validated by comparison with other method based in a Modified Wheatstone Bridge. Evaluation of measurement uncertainty is also validated.