Design and evaluation of a low thermal electromotive force guarded scanner for resistance measurements

Jarrett, Dean G.; Marshall, James A.R.; Marshall, Thomas A.; Dziuba, Ronald F.

doi:10.1063/1.1149810

Cited by 10 publications

(2 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Accurate and f ully automated substitution measurements can be performed using a guarded scanner for nominal values up to 10 GΩ. The low-thermal guarded scanner [24] was developed commercially in cooperation with NIST and is used for high-resistance levels up to 1 G Ω.…”

Section: Automatic Resistor Selectionmentioning

confidence: 99%

NIST measurement service for DC standard resistors

Dziuba¹,

Jarrett²,

Jones³

et al. 2003

View full text Add to dashboard Cite

At the National Institute of Standards and Technology (NIST), the U.S. representation of the ohm is based on the quantum Hall effect, and it is maintained and disseminated at various resistance levels by working reference groups of standards. This document describes the measurement systems and procedures used to calibrate standard resistors and current shunts of nominal decade values in the resistance range from 10 −5 Ω to 10 12 Ω. Resistance scaling techniques used to assign values to the working standards are discussed. Also included is an assessment of the calibration uncertainties at each resistance level. * The abbreviation ppm (parts-per-million) is used in place of an equivalent SI ratio such as µΩ/Ω or µV/V when it does not appear in combination with SI terms.* Evanohm is a commercial alloy having a resistivity of about 1.34 µΩ-m with a nominal composition of 75 % Ni, 20 % Cr, 2.5 % Cu, and 2.5 % Al. By suitable annealing and heat treatment, its TCR can be adjusted to nearly zero from (20 to 30) °C.

show abstract

Section: Automatic Resistor Selectionmentioning

confidence: 99%

NIST measurement service for DC standard resistors

Dziuba¹,

Jarrett²,

Jones³

et al. 2003

View full text Add to dashboard Cite

show abstract

“…However, this system still has a drawback in that the terminal configuration of instruments needs to be manually changed according to the quantity to be measured (i.e., AC voltage, DC voltage, AC current, DC current, and resistance). To overcome this problem, a fully automatic system has been developed using a built-up low thermal scanner to control the instruments and process the measurement [5,6].…”

Section: Introductionmentioning

confidence: 99%

Characterization of developed low thermal scanner for DC voltage measurement

Munir¹,

Azzumar²,

Syahadi³

2023

Eng. Res. Express

View full text Add to dashboard Cite

A low thermal scanner has been completely developed for improving DC voltage calibration from semi-automatic to fully automatic measurement system. The application of the switching system inside the built-up scanner introduced offset voltage to the measurement due to thermal electromotive force (EMF). A differential measurement method was proposed to characterize the thermal EMF of the scanner, and this method has been compared to previous characterization using the direct measurement method. The results show that the differential measurement method could minimize the thermal EMF effect, and the thermal EMF had a negligible contribution to the measurement for uncertainty levels around 10 to 11 ppm. Therefore, the differential measurement method is recommended for DC voltage calibration with uncertainty levels below 10 ppm since the thermal EMF can significantly affect the measurement. Furthermore, the direct measurement method is suggested for DC voltage calibration with uncertainty levels above 11 ppm since it can speed up the measurement process.

show abstract