EP 0198632 A2 19861022 - Electronic ballast for fluorescent lamps.
Title (en)
Electronic ballast for fluorescent lamps.
Title (de)
Elektronisches Vorschaltgerät für Leuchtstofflampen.
Title (fr)
Ballast électronique pour lampe fluorescente.
Publication
Application
Priority
GB 8508913 A 19850404
Abstract (en)
An electronic ballast for a discharge lamp has a transistor-oscillator arrangement comprising a single transistor (TS), whose base is coupled to be driven via a feedback winding (L4) of a transformer (TR1). A primary winding (L3) of the transformer forms part of a resonant circuit connected in the collector path of the transistor. A secondary winding (L5) of the transformer is connected across a discharge lamp (1) for the supply of high frequency alternating voltage to the lamp. The transistor is biased into class A operation, by a biasing means (R2, R3). This biasing means can also be used as a dimmer by adjusting the operation of the transistor along its characteristic curve to alter the collector voltage. The ballast has lamp connector terminals, 4, 5 a first one 4 of the terminals being connected to an a.c. voltage supply (L), and the second of the connector terminals (5) being connected to a rectifying means (D1-D4). This ensures that the ballast only operates when an operative filament (2) is connected between the lamp connector terminal (4, 5). Mains supply voltage is filtered by a line filter L1, I2, C1-C3.
IPC 1-7
IPC 8 full level
H05B 41/298 (2006.01)
CPC (source: EP)
H05B 41/2985 (2013.01)
Designated contracting state (EPC)
AT BE CH DE FR GB IT LI LU NL SE
DOCDB simple family (publication)
EP 0198632 A2 19861022; EP 0198632 A3 19870325; GB 8508913 D0 19850509
DOCDB simple family (application)
EP 86302471 A 19860403; GB 8508913 A 19850404