GB745899A - Circuit for the ignition of fluorescent lamps - Google Patents

Abstract

745,899. Supply systems for space discharge tubes. SCHULER, E. June 23, 1952 [Sept. 13, 1951], No. 15734/52. Class 38 (4). [Also in Group XXXVII] In an ignition circuit for thermionic electrode fluorescent discharge lamps, the electrodes are initially heated by being connected to an A.C. supply in a series circuit which also includes an inductance L and the heater element 8 and normally closed contacts of a bimetal strip switch 7, after a period of heating of the switch 7 the latter opens its contacts to cause operation of a voltage-controlled electromagnetic relay having its energizing coil 6 connected in parallel with the lamp and which relay holds the switch contacts open, the relay operates a pair of interrupter contacts 19, 20 which cause repeated short-circuiting of a condenser 5 series-connected with the inductance L across the supply whereby voltage peaks are applied to the lamp to cause it to strike, and striking of the lamp causes such reduction of the relay coil voltage that the relay no longer operates the interrupter contacts 19, 20 but continues to hold open the bimetal switch contacts. The condenser 5 is serially connected with a resistance and is disposed together with the switch and relay in a common casing 1 having two contact-pins 3, 3a.