Patent ID: 6873122

Claim:
An apparatus for operating at least two discharge lamps, comprising: a first contact device ( 13 , 14 ) for electrically connecting a first discharge lamp ( 7 ) having two first incandescent filaments, a second contact device ( 13 a , 14 a ) for electrically connecting a second discharge lamp ( 7 a ) having two second incandescent filaments, wherein the first and second contact devices are connected in series, a first PTC thermistor ( 9 ), connected in parallel with the first contact device, for controlling the current through the two first incandescent filaments, a second PTC thermistor ( 9 a ), connected in parallel with the second contact device, for controlling the current through the two second incandescent filaments, a resonant capacitor ( 8 ) connected in parallel with the first and second contact devices, and a first series capacitor ( 12 ) connected in series with the first PTC thermistor.