Discharge lamp operating circuit
AssigneeGeneral Electric Company
InventorWayne R. Neal
Life of this patent
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Abstract
Color rendition of high pressure sodium vapor discharge lamps is improved by disclosed operating circuit for applying pulsed direct current to the lamp. The circuit includes a direct current ballast circuit having a low ripple factor, a filter capacitor charged by the output of the ballast circuit, and a pulsing circuit comprising a transistor switch which operates to apply DC pulses on the lamp at a predetermined repetition rate and duty cycle to provide desired color properties of the lamp.
Claims7
A lamp operating circuit comprising, in combination, a source of alternating current, current limiting reactance means comprising a first induction coil connected to said alternating current source, and auxiliary induction coil inductively coupled to said first induction coil, first rectifier means connected to the output of said first induction coil, said first induction coil being connected in series between said alternating current source and said first rectifier means, second rectifier means connected to the output of said auxiliary induction coil, and a DC pulsing circuit connected to said first and second rectifier means and comprising unidirectional controlled switch means and an inductor connected in series to said first and second rectifier means, means for serially connecting a gaseous discharge lamp in said DC pulsing circuit, diode means connected across the series connected inductor and lamp connecting means, and control means connected to said unidirectional controlled switch means for intermittently operating the same at predetermined intervals, whereby DC pulses are applied to the gaseous discharge lamp for operation thereof.
Dependencies are inferred from the claim text.