OFFSET
15,1
COMMENTS
The value of K(J-90) is 483597.9 * 10^9 Hz V^-1 based on measurements in 1990. - Ralf Steiner, Jan 03 2019
The value of K(J) is 2 * e / h = 483597.848416... * 10^9 Hz V^-1 based on SI definitions (effective on May 20, 2019). - Ralf Steiner, Jan 03 2019
From Wolfdieter Lang, May 20 2019: (Start)
For the seven units of the 2019 SI system see A322415 with references.
Here only the Planck constant h = 6.62607015*10^{-34} J s, with J = kg m^2 s^(-2), and the elementary charge e = 1.602176634*10^{-19} C, with C = A s are used.
The 1990 definition of Volt with symbol V is K_{J-90} = (V s)^{-1}, where s^(-1) = Δν_{Cs}/9192631770. (End)
LINKS
BIPM, On the revision of the International System of Units (SI), BIPM, Nov 13-16 2018.
NIST, Josephson constant
Wikipedia, Josephson effect
EXAMPLE
K_J = 2*e/h = 4.83597848416983632447658285054528135353351186600401446096974992032041797... * 10^14 A s^2/(kg m^2). - Wolfdieter Lang, May 20 2019
MATHEMATICA
RealDigits[2*(1.602176634`100*10^(-19))/(6.62607015`100*10^(-34))][[1]]
PROG
(PARI) 21362355120000000000000/44173801 \\ Charles R Greathouse IV, Jul 16 2023
CROSSREFS
KEYWORD
AUTHOR
Arkadiusz Wesolowski, Oct 07 2014
EXTENSIONS
Updated by Ralf Steiner, Jan 03 2019
STATUS
approved