A proposal for a toroidal cross-capacitor

A proposal which describes the feasibility of both a secondary and an absolute transportable standard of capacitance having fixed intrinsic values rather then corresponding to a change of capacitance is illustrated. This has been achieved by the toroidal cross-capacitor (TCC) form which is exempt from "end" effects: The proposal evaluates the best form of the ring electrodes and the features of their design to fulfil this purpose with a relative uncertainty of a few parts in 10/sup -8/ for a capacitance value in the range from 0.6 pF to 1.65 pF.