Analytical expressions describing the input current spectrum of the flyback Pulse-Width-Modulated, Zero-Current-Switched Quasi-Resonant-Converter, and Zero-Voltage-Switched Quasi-Resonant-Converter are derived in terms of normalized circuit parameters. These analytical results are tested against experimental results. The same numerical example is presented for these three converters in which the input current spectrum is computed for various line/load conditions and the results are mutually compared. Detailed experimental results are presented for the same three converters as well as for the flyback Zero-Voltage-Switched Multi-Resonant-Converter. The effects of any parasitic oscillations in the experimental circuit are also considered. / Master of Science