Re-defining the kilogram via a moving-coil apparatus

The goal of basing the definition of the kilogram on voltage and resistance measurements in terms of the Josephson and quantum Hall effects, which have an accuracy of 1 in 10/sup 9/, is addressed. The problems of accomplishing this using a moving-coil apparatus are discussed. In particular, consideration is given to measuring the voltage accurately enough, eliminating the refractive index of air, the stability of the magnetic flux density, interaction of the current in the coil with the magnetic circuit, reducing floor vibration and eliminating its effects, measuring g, and alignment problems.<
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