A modified Current-Fed Push-Pull Parallel Resonant Inverter (CFPPRI), that includes diodes in series with the switches, was analyzed and tested by simulation and experimentally. The modified power source is capable of producing a low THD output voltage within a relatively wide frequency range. A comparison between the modified topology and the basic CFPPRI, in terms of output signal quality and efficiency was carried out. It was found that the modified inverter is more efficient and that it produces an output signal that is less distorted as the running frequency deviates from resonance. Operation with a capacitive load in an off-resonance mode was demonstrated by driving a rotary piezoelectric motor by the modified inverter.