Abstract: A lighting control system for discharge lamps which comprises a ballast for supplying energy from a power source to a lamp. First and second capacitors and a first control relay and contact set control the supply of energy from the ballast to the lamp to switch the lamp between dimmed and normal wattage operational modes. A second control relay and contact set connects a single output control wire to neutral when a predetermined condition is sensed or a switch is thrown. The first control relay, which is connected at one end to the lamp ballast, is energized when the other end thereof is connected to neutral via the second control relay. The first control relay in turn closes the normally open contact set, which is connected to one of the capacitors, to increase the energy provided to the lamp. In accordance with one embodiment the first capacitor and the contact set of the first control relay are connected in series, and together are connected parallel to the second capacitor.

Abstract: A discharge lamp operating circuit is connected to a source of alternating current (AC) voltage, and has a discharge lamp and a semi-resonant circuit connected to the source of alternating current voltage and in series with the lamp. A starting circuit for initiating operation of said discharge lamp is also connected in the circuit. The lamp switching maintains the series semi-resonant circuit in oscillation and the series semi-resonant circuit maintains the lamp in operation after operation has been initiated by the starting circuit. Highly efficient energy transfer between inductive and capacitive components of the system result in low loss and high power factor. A variable capacitance circuit is provided to allow use of the discharge lamp operating circuit with different line voltages, and to allow dimming.

Abstract: A discharge lamp operating circuit is connected to a source of alternating current (AC) voltage, and has a discharge lamp and a semi-resonant circuit connected to the source of alternating current voltage and in series with the lamp. A starting circuit for initiating operation of said discharge lamp is also connected in the circuit. The lamp switching maintains the series semi-resonant circuit in oscillation and the series semi-resonant circuit maintains the lamp in operation after operation has been initiated by the starting circuit. Highly efficient energy transfer between inductive and capacitive components of the system result in low loss and high power factor.