• standard capacitor;
  • capacitance;
  • calibration;
  • uncertainty


The National Metrology Institute of Japan (NMIJ) has developed a new national standard of capacitance (capacitance standard) and also established its traceability system. Calibration and measurement capabilities (CMCs) of the new capacitance standard were validated in the international comparison with foreign National Metrology Institutes (NMIs). However, it is not easy to frequently carry out such international comparison which requires close coordination among the participating NMIs. In order to maintain high reliability of the capacitance standard, therefore, it is important to verify its CMCs during the period when the comparisons are not carried out. To verify the CMCs, NMIJ has been performing long-term monitoring of standard capacitors and of capacitance differences among a number of standard capacitors. In this paper, we will report the details of the long-term monitoring of the standard capacitor, the long-term monitoring results of capacitance differences, and verification of CMCs based on the analysis of these results. Validation of the CMCs based on results of monitoring conducted after the massive earthquake on March 11, 2011 is also described as specific case. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.