An electrical generator includes one or more magnets that move relative to one or more conductors to generate an electrical signal in each conductor. Each magnet has ferrofluid bearings in the vicinity of its opposite ends to provide a low friction interface between the magnet and a support structure. The ferrofluid bearings establish a field expansion medium that directs at least a portion of the magnetic field so that a greater portion of the field intersects the conductors than in the absence of the medium. The magnet aspect ratio is preferably on the order of unity.