Method and apparatus for dimming fluorescent lights
AssigneeElectro Controls Inc.
InventorRuel Clark
Life of this patent
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Abstract
A dimmer for fluorescent lights utilizes a standard A.C. phase control at normal line A.C. frequencies to control the line power to the standard fluorescent light ballast and thereby control the illumination level of the light. During the "off" time of the A.C. line signal, a high frequency signal is applied to the ballast which supplies additional power through the ballast to the filament of the light but is substantially blocked by the ballast from the discharge portion of the light so does not substantially affect the illuminating output of the light.
Claims21
A dimmer for fluorescent lights that utilizes the standard ballast associated with the lights, comprising means for controlling the transmission of the normal line A.C. voltage sine wave to the ballast so that the A.C. voltage is connected to the ballast for only a selectable period of time during each half cycle of the sine wave and is blocked during the remaining period of each half cycle thereby controlling the power supplied to the discharge portion of the lights to control brightness;
- and means for applying a high frequency voltage signal to the ballast during at least a portion of the time period when the A.C. signal to the ballast is blocked thereby supplying additional power to the filaments of lights.
Dependencies are inferred from the claim text.