Capacitively ballasted low voltage incandescent lamp
AssigneeGeneral Electric Company
InventorPaul T. Cote
Life of this patent
Estimating the term…
Abstract
A capacitively ballasted low voltage lamp utilizing a main capacitor connected electrically in series with the lamp, across an alternating current source, and one or more auxiliary capacitors that can be connected electrically across the main capacitor by switching means for one or more source waveform cycles. Each switching means comprises a unidirectional conductive device electrically connected in parallel with an active switching device. The minimum lamp current is established by the main capacitor, with additional lamp current flowing through one or more auxiliary capacitors during a source waveform cycle or integral multiples thereof.
Claims7
A ballast means controlling power from an alternating current source to an incandescent lamp, having a filament, at a voltage magnitude that is less than the alternating source voltage comprising:
- (a) a first capacitive element electrically serially connected to said lamp which together are across the ballast means input terminal;
- (b) at least one auxiliary capacitive element
- (c) a control means connected across the filament of said lamp generating discrete control signals in response to conditions of the current flowing through the filament;
- and,
- (d) transistor switching means capable of operating at a temperature of at least 130.degree. C., responsive to said control means so as to be rendered conductive for one or more complete cycles of alternating current in response to said control signal, for selectively and individually electrically connecting each auxiliary capacitive element in parallel across said first capacitive element, wherein each auxiliary capacitive element has serially connected thereto a switching means comprising a unidirectional conducting device connected electrically in parallel with an active switching device.
A ballast means controlling power from an alternating source to an incandescent lamp, having a filament, at a voltage magnitude that is less than the alternating voltage source comprising:
- (a) a first capacitive element electrically connected to said lamp which together are across the ballast means input terminal;
- (b) at least one auxiliary capacitive element;
- (c) a control means connected across the filament of said lamp generating a control signal in response to the conditions of the current flowing through the filament;
- (d) transistor switching means capable of operating at a temperature of at least 130.degree., responsive to said control means so as to be rendered conductive for one or more complete cycles of alternating current in response to said control signal, for electrically connecting each auxiliary capacitive element in parallel across said first capacitive element, wherein each auxiliary capacitive element has serially connected thereto a switching means comprised of a unidirectional conductor device connected electricaly in parallel with an active switching means, and further;
- wherein each auxiliary capacitive element has values selected so that at the time it is electrically connected in parallel with said first capacitive element by said switching means in response to said control means, the voltage potential across each of auxiliary capacitor element, which is electrically connected in parallel with said first capacitive element, is approximately the same as the voltage potential across said first capacitive element.
Dependencies are inferred from the claim text.