a lamp driving apparatus wherein a plurality of two - winding balance circuits are connected to a plurality of parallel - connected lamp groups so that all of the lamps may be illuminated even though ambient conditions cause some of the lamps to have low resistance . capacitors are connected to first electrodes and certain of the balance coil windings are connected to second electrodes of one of the lamp groups while , in a second lamp group , others of the balance coil windings are connected to the first electrodes and capacitors are connected to the second electrodes thereof , current flowing through balance coil windings to some lamps being affected by current flowing through balance coil windings to other lamps .