Recent NPL work on e/h

  • J. C. Gallop
  • B. W. Petley
Conference paper


Measurements of 2e/h using the a.c. Josephson effect have been made at the NPL over a three year period with increasing precision. The latest determination is reported here and it is estimated that the overall uncertainty has been reduced to the point where the experiment may be regarded as a means of monitoring variations in the national maintained voltage standard. The existence of similar experiments at several national standards laboratories should enable the international voltage standards to be compared in addition to the international BIPM volt comparison.


Josephson Junction Standard Cell Fundamental Constant Josephson Effect Helical Spring 
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  1. 1.
    PETLEY, B.W. and MORRIS, K., Metrologia, 6, (2), 46 (1970).ADSCrossRefGoogle Scholar
  2. 2.
    PETLEY, B.W. and GALLOP, J.C., Proceedings of the International Conference on Precision Measurement and Fundamental Constants, Nat. B.r. Stds. Special Publication 343 (1971).Google Scholar

Copyright information

© Plenum Publishing Company Ltd 1972

Authors and Affiliations

  • J. C. Gallop
    • 1
  • B. W. Petley
    • 1
  1. 1.Division of Quantum MetrologyNational Physical LaboratoryTeddingtonEngland

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