Amplitude, frequency, and waveform control of a homopolar generator

From an experimental study of the motional electromotive force, the author has evolved a technique of rotating contactors applied to a conducting cylinder in a nonuniform magnetic field. When this method of sliding brush pick-offs is applied to a conducting flat disk, interesting possibilities become apparent. Alternating currents that have their source in a motionally developed emf can be controlled mechanically as to amplitude, frequency, and waveform