Williams, E.
, Steiner, R.
and Newell, D.
(1998),
An Accurate Measurement of Planck's Constant, Physical Review Letters
(Accessed March 28, 2026)
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
An Accurate Measurement of Planck's Constant
Published
Author(s)
, ,
Abstract
Using a moving coil watt balance, electric power measured in terms of the Josephson and quantum Hall effects is compared with mechanical power measured in terms of the meter, kilogram and second, we find the Planck constant h = 6.62606891(58) x 10-34 Js. The quoted standard uncertainty ( 1 standard deviation estimate) corresponds to (8.7 x 10-8) h. Comparing this measurement places an upper limit of 2 x 10-8 / year on the drift rate of the SI unit of mass, the Kilogram.Citation
Physical Review Letters
Pub Type
Journals
Keywords
electron mass, fundamental constants, Josephson constants, kilogram, mass drift, Planck constant, Watt-SI
Citation
Issues
If you have any questions about this publication or are having problems accessing it, please contact [email protected].
Created June 30, 1998, Updated October 12, 2021