An electronic ballast is adapted for operation on regular 120 volt/60 Hz power line voltage and comprises: (i) full bridge rectifier means, (ii) ripple filter means consisting of an LC circuit series- resonant at 120 Hz, (iii) self-oscillating inverter means operating into an LC output circuit parallel-resonant at about 30 kHz, and (iv) means to disable the inverter in case a 30 kHz ground-fault current flows from its output circuit. A key element in achieving high reliability as well as high durability relates to the use of the series-resonant LC circuit instead of the conventional electrolytic capacitor for DC voltage ripple filtering. A key element in achieving high efficiency relates to the use of ground-fault interruption to achieve the required safety from electric shock hazard, thereby obviating the need for the more conventionally used isolation transformer with its attendant added cost and inefficiency.
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