A Four-Terminal Current Shunt with Calculable AC Response

The design of a 0.1, four-terminal current shunt with calculable frequency dependence up to 1 MHz is described. It is intended for use as a standard for current measurements up to 10 A rms with the primary purpose of being able to tie alternating-current measurements to direct-current measurements. The shunt is of the bifilar flat-strip configuration where the effects of self-inductance, skin effect, capacitance, dissipation factor, and eddy-current losses are considered. Contributions of the individual effects, where applicable, are determined by calculation based on geometry and corroborated by differential measurements and finite-element field simulations. The uncertainties due to dimensional and electrical measurement tolerances are computed as well.