Characterisation of Zener-diode-based electronic voltage standards.

In order to make optimum use of a group of Zener-diode-based electronic voltage standards as a laboratory standard for emf, it is necessary to characterise the individual standards in terms of temporal drift and the effects of environmental influences. An experimental set-up for the measurement of the temperature and pressure coefficients of electronic voltage standards is described and the results obtained for a number of commercial electronic voltage standards presented. The improvement in the overall accuracy of the group standard resulting from applying temperature and pressure corrections using derived coefficients is given.