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The invented VIRT includes a fractional, reconfigurable effective turns ratios for a transformer. This structure yields AC currents flowing in only fractions of a complete turn prior to rectification, enabling reduced conduction loss as compared to previous designs. The VIRT comprises a series of switching cells distributed around a magnetic core and coupled to half-turns wound through that core. By controlling operating modes of the switching cells, it is possible to control over flux paths and current paths in the transformer. The VIRT is valuable in converters with wide operating voltage ranges and high step-up/down, as it offers a means of reducing turns count and copper loss within a transformer while facilitating voltage doubling and quadrupling. The fractional turns also enable planar transformers which offer potential for improved fabrication and miniaturization, especially on a printed circuit board.