A new standard for direct current
F.C. Fitchen, F. P. Schwieg, W. H. Tucker · Transactions of the American Institute of Electrical Engineers Part I Communication and Electronics · 1955
A practical standard for direct current has been developed and is incorporated into a high-accuracy measuring instrument. Utilizing the stability of a permanent magnet, this device may be stored and used under extreme conditions of temperature, and it is relatively insensitive to variation in operating conditions.