A determination of Planck's constant using the NRC watt balance

Abstract

We have measured Planck's constant and have obtained a value of 6.626 070 34(12) × 10−34 J s. To our knowledge this measurement of h has the lowest uncertainty reported to date. This result has been obtained from measurements of four masses of different material and nominal values varying from 1 kg to 250 g. The experimental procedures and the measurement uncertainties are described in detail.