GB1103540A - Fluorescent lamp-dimming circuit - Google Patents
Fluorescent lamp-dimming circuitInfo
- Publication number
- GB1103540A GB1103540A GB4654866A GB4654866A GB1103540A GB 1103540 A GB1103540 A GB 1103540A GB 4654866 A GB4654866 A GB 4654866A GB 4654866 A GB4654866 A GB 4654866A GB 1103540 A GB1103540 A GB 1103540A
- Authority
- GB
- United Kingdom
- Prior art keywords
- contacts
- circuit
- lamps
- auto
- members
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/36—Controlling
- H05B41/38—Controlling the intensity of light
- H05B41/40—Controlling the intensity of light discontinuously
- H05B41/42—Controlling the intensity of light discontinuously in two steps only
Abstract
1,103,540. Dimming arrangements for fluorescent lamps. BRITISH LIGHTING INDUSTRIES Ltd. 18 Oct., 1966, No. 46548/66. Heading H2H. A circuit for operating parallel-connected filament-heated fluorescent lamps 10, 11 at normal or reduced illumination comprises a three-position switch 12 controlling a relay coil R having contacts rl, r2, r3, the arrangement being such that in one position (bright) of the switch 12 the coil is de-energized and the lamps are supplied from an auto-transformer winding 17 through contacts r2, respective ballast members 19, 21, 22 and respective contacts rl, r3, while in another position (dim) the coil is energized to insert resistors 18, 20 in series with the respective lamps and to change over the contacts r2so that the lamps are supplied with increased voltage from the auto-transformer 17 to maintain the stability of operation at low current densities. Capacitors 24, 25 reduce lamp shimmer in the dim condition and a resistor 23 prevents excess current should contacts rl, r3 fail to open. Interference suppression capacitors 26, 27 are connected so as to be effective in both conditions of the circuit. In an arrangement to supply a single lamp, Fig. 2 (not shown), the auto-transformer (17<SP>1</SP>) supplies the filament heating current and a third set of relay contacts (r<SP>1</SP>3) controls a power factor capacitor (28) connected across the supply terminals L, N. The circuit of Fig. 1 may be modified by connecting the members 19, 21, 22 in series with the respective contacts rl, r2 across respective resistors 18, 20 so that these members are out of circuit in the dim condition.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB4654866A GB1103540A (en) | 1966-10-18 | 1966-10-18 | Fluorescent lamp-dimming circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB4654866A GB1103540A (en) | 1966-10-18 | 1966-10-18 | Fluorescent lamp-dimming circuit |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1103540A true GB1103540A (en) | 1968-02-14 |
Family
ID=10441680
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB4654866A Expired GB1103540A (en) | 1966-10-18 | 1966-10-18 | Fluorescent lamp-dimming circuit |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB1103540A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2313839A1 (en) * | 1975-02-24 | 1976-12-31 | Stl | Power stabilisation for discharge lamps - uses transformer to maintain voltage at higher level than supply voltage |
-
1966
- 1966-10-18 GB GB4654866A patent/GB1103540A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2313839A1 (en) * | 1975-02-24 | 1976-12-31 | Stl | Power stabilisation for discharge lamps - uses transformer to maintain voltage at higher level than supply voltage |
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