Primary state standard of the unit of inductance — The henry

Conclusions

The standard of the henry is the first (with respect to its approval) state standard in the range of inductance, capacitance, and resistance measurements.

This standard served up to the beginning of the sixties as the only initial (computed) quantity, on whose basis the VNIIM determined by indirect means the absolute values of the units of capacitance and resistance. The error of these indirect methods for reproducing units was of the order of 10⁻⁵.

Investigations, including circulatory international comparisons, of working standards have shown that the precision and accuracy of reproducing inductance units in the USSR are at the level of the best results obtained in national metrological institutes.

In recent years new, more precise methods for reproducing resistance units have appeared. These methods, as well as the application of new types of measuring equipment, made it possible to extend substantially the nominal values' range of inductance standards covered by the test schematic.

In order to ensure uniformity in this field of measurements, it is necessary to have a set of mutually-related computed inductance and capacitance standards (Fig. 3).

The State Committee of standards attached to the USSR Council of Ministers approved, in accordance with the VNIIM recommendations, the coil types PB-1, KB-1, KB-2, and KB-3 as primary state standards of the henry. Prof. Igor' Nikolaevich Krotkov,head of the VNIIM laboratory,was appointed scientific keeper of this State standard.