Unequalized currents in coaxial AC bridges

In a coaxial ac bridge with imperfect current equalization, the comparison of two standard resistors shows a linear frequency dependence. Unequalized currents load the magnetic cores in the coaxial bridge and result in effective loss factors of certain capacitances of the compared resistors. To avoid this systematic effect in any coaxial bridge used for the precise calibration of impedance standards, a correct arrangement of current equalizers is absolutely necessary.