Abstract: An ozonizer power feeding device comprising a multiphase power source having at least one terminal for each phase, a thyristor circuit coupled to the terminals of the power source and including at least two thyristors for each phase connected at one side thereof in an anti-parallel configuration to a respective terminal of the source, a transformer having at least one primary coil coupled to the other sides of the anti-parallel connected thyristors and a secondary coil adapted to be connected to an ozonizer for feeding power to the ozonizer, and a joint control unit coupled to each of the thyristors for controlling the conduction time thereof in dependence on the waveforms provided at the terminals of the source in order to derive a composite waveform applied to the transformer primary, wherein the composite waveform has a high frequency than that of any of the phases of the power source, thereby increasing ozone production which is proportional to the frequency of the applied power.