Abstract: A modulated electronic ballast for driving a gas discharge lamp includes a full wave rectifier for supplying a modulating signal to a series fed parallel resonant circuit including two transistors. Inductors are provided on both the hot and neutral alternating current power source lines for shielding the power source from electromagnetic interference and providing transient protection. A biasing circuit supplies a small direct current to the resonant circuit for retaining the resonant circuit in a continuous oscillating mode during substantially zero voltage valleys of the modulating signal. A diode is provided across the base and collectors of each transistor in the resonant circuit for preventing over saturation and co-conduction.

Abstract: A ballast circuit enclosure and grounding structure for electrically grounding a ballast circuit to a housing and for capturing transmitted RFI and EMI therefrom. The ballast circuit enclosure includes an elongate housing for receiving and surrounding the ballast circuit. End caps are attached to the housing opposite open ends in closing engagement with the housing. The end caps are fastened to the housing with fastening members extending through holes in the end caps and into elongate channels formed on the inside of the housing. The ballast circuit board rests on elongate abutment shoulders within the housing and is sandwiched between the abutment shoulders and longitudinal walls forming the elongate channels. A grounding wire on the edge of the circuit board is coupled to the ballast circuit and is in electrical contact with the fastening member and/or the channel forming elongate wall of the housing.