Planck constant

The Planck constant ($h$), is named after the German physicist Max Karl Ernst Ludwig Planck. Its value (in SI units, 2006 CODATA (Ref. 1)) is:

$6.62606896(33)\times 10^{-34}\mathrm{J}\mathrm{s}$

More recent measurements place a preliminary value at $6.62607095(44)\times 10^{-34}\mathrm{J}\mathrm{s}$ (Ref. 2)

References

1. Peter J. Mohr, Barry N. Taylor, and David B. Newell "CODATA recommended values of the fundamental physical constants: 2006", Reviews of Modern Physics 80 633 (2008)
2. I A Robinson and B P Kibble "An initial measurement of Planck's constant using the NPL Mark II watt balance", Metrologia 44 pp. 427-440 (2007)