Current-transformer methods of producing small, known voltages and currents at radio frequencies for calibrating purposes

摘要

A method is outlined whereby known, small radio-frequency voltages may be produced. The method consists of an arrangement of a current transformer, across the secondary of which is a suitable resistance of known value. A thermo-junction or other device serves to measure or to set the primary current. Voltages from a few microvolts to a few tenths of a volt may be conveniently produced. The nature and extent of the errors of the method are discussed, and the precautions necessary to reduce these to a negligible amount are indicated. Various uses of the method are touched upon and the limitations of the method are given. An appendix gives a simple analytical treatment of the iron losses in the core of a current transformer at radio frequencies, in so far as these affect the ratio of the transformer. The phase displacement of the currents is, however, not discussed.