Starting and dimming circuit for fluorescent lamps
US4559479A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 28, 1984 |
| Grant date | Dec 17, 1985 |
| Priority date | — |
| Expiry date | Mar 28, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A rapid start circuit for starting and step dimming a fluorescent lamp includes a voltage step up auto transformer and lamp filaments for starting, ballast and a pair of capacitors having different values variously connected in series with the lamp and ballast by a rotary switch; first in parallel, then individually and then in series to achieve a progressively stepped dimming of the lamp. A second form of the invention includes a first capacitor in series with the lamp and ballast for reducing the maximum light output of the lamp and a plurality of capacitors each having a different value selectively connected in parallel with the first capacitor by a slide switch to selectively dim the lamp; and a resistor in series with the first capacitor to diminish arcing and noise when switching. Both forms of the invention include a pair of secondary windings for maintaining filament voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.