Cross conductivity standard for nonferrous metals at NIM

A so called "cross conductivity standard" based on a new principle developed from Thompson-Lampard Theorem (1956) has been established at NIM by the end of 1992. The conductivity range of the standard is approximately from 3% IACS to 100% IACS and with an uncertainty about 0.07%. By using an AC measuring system and a new method, the unknowns can be calibrated with an uncertainty of (0.1% /spl sigma/x+0.12% IACS).<>