The operation of a class-E-derived single-ended parallel-resonant convertor is examined both theoretically and practically. The convertor topology is produced from the electric-circuit dual of the class E convertor by the addition of a diode in antiparallel with the switching transistor. The resulting convertor exhibits zero-current-switching characteristics. A fundamental-frequency analysis of the convertor is presented which defines the limits of zero-current switching and the convertor conversion characteristics. Experimental results from a prototype convertor are presented.