Model tests to investigate the effects of geometrical imperfections on the NIST calculable capacitor

Author

Jeffery, Anne-Marie ; Lee, Lai H. ; Shields, John Q.

Author_Institution

Electron. & Electr. Eng. Lab., Nat. Inst. of Stand. & Technol., Gaithersburg, MD, USA

Volume

48

Issue

2

fYear

1999

fDate

4/1/1999 12:00:00 AM

Firstpage

356

Lastpage

359

Abstract

The calculable capacitor at National Institute of Standards and Technology (NIST) links the U.S. capacitance unit to the SI unit and has a relative standard uncertainty of 2×10^-8. Geometrical imperfections are one of the largest sources of this uncertainty. Tests with a model calculable capacitor have been done to better evaluate and reduce this uncertainty. These included evaluations of the effect of eccentricity of the blocking electrodes used to define the capacitor´s length and of uniform taper on all the calculable capacitor bars. In addition, the effect of tilt of the blocking electrode and taper in three or fewer bars was investigated. A new cone-shape for the tip of the blocking electrode was also studied

Keywords

capacitance measurement; capacitors; measurement standards; measurement uncertainty; NIST calculable capacitor; SI unit; blocking electrodes; capacitance unit; capacitor bars; cone-shape; cross-capacitor; eccentricity effect; electrode tip; geometrical imperfections effect; model tests; relative standard uncertainty; tilt effect; uniform taper; Bars; Capacitance measurement; Capacitors; Electrodes; Length measurement; NIST; Optical interferometry; Solid modeling; Testing; Uncertainty;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.769600

Filename

769600