초록 ▼

A lightweight, transistorized, inverter circuit is particularly adapted for starting and operating a screw-in compact fluorescent lamp intended for incandescent lamp replacement. Household-type AC is converted to DC with one terminal connected to the center tap of a transformer primary through a cho

A lightweight, transistorized, inverter circuit is particularly adapted for starting and operating a screw-in compact fluorescent lamp intended for incandescent lamp replacement. Household-type AC is converted to DC with one terminal connected to the center tap of a transformer primary through a choke which constitutes a high impedance at the operating frequency. A tuned circuit capacitor is connected across the transformer primary and a current-limiting capacitor and the lamp to be operated are connected in series across the transformer primary. A pair of transistors are connected in push-pull arrangement between the end portions of the transformer primary and the other terminal of the DC source, with the base electrodes of the transistors connected to the transformer secondary winding so that the push-pull connected transistors oscillate at the tuned circuit resonant frequency which is determined by the inductance of the transformer primary winding and the total capacitance of the connected capacitor means. A potential is applied to the midpoint of the transformer secondary upon energization of the apparatus in order to initiate transistor conduction. The system operates with a high efficacy for the production of light.

대표청구항 ▼

A starting and operating apparatus for a fluorescent lamp having one electrode adapted to be preheated to facilitate lamp starting comprising: apparatus input terminals adapted to be connected across a source of AC energizing potential, and apparatus output terminals across which the lamp to be oper

A starting and operating apparatus for a fluorescent lamp having one electrode adapted to be preheated to facilitate lamp starting comprising: apparatus input terminals adapted to be connected across a source of AC energizing potential, and apparatus output terminals across which the lamp to be operated is adapted to be connected in circuit; AC to DC conversion means having input terminals and output terminals, said conversion means input terminals connected to said apparatus input terminals and said conversion means operable to convert said AC potential to predetermined DC potential which is developed across said conversion means output terminals; transformer means having a primary winding of predetermined inductance and a secondary winding, said transformer means primary winding connected at its mid-point via a choke to one output terminal of said conversion means, tuned circuit capacitor means of predetermined capacitance connected across said transformer means primary winding to form therewith a first resonant tuned circuit when said lamp is connected in circuit but is not operating, a current-limiting capacitor means connected in series with said lamp as connected in circuit, said series-connected lamp and current-limiting capacitor means being connected in parallel with said tuned circuit capacitor means, and said current-limiting capacitor means and said tuned circuit capacitor means forming with said transformer means primary winding a second tuned circuit when said lamp is connected in circuit and is operating; a pair of transistors connected in push-pull arrangement in circuit between the ends of said transformer means primary winding and the other output terminal of said conversion means, the base electrodes of said transistors being connected across said transformer means secondary winding so that the push-pull connected transistors oscillate at the tuned circuit resonant frequency as determined by the inductance of said transformer means primary winding and the total capacitance of said connected capacitor means, and means for applying a potential from said one output terminal of said conversion means to the midpoint of said transformer means secondary winding to initiate transistor conduction upon energization of said apparatus, and when said lamp is connected to said apparatus output terminals, said preheatable electrode is connected in electrical circuit intermediate one end of said transformer means primary winding and said tuned circuit capacitor means so as to effect electrode preheating.