A starting and operating circuit for gaseous discharge lamps which includes a pair of input terminals for connection to an alternating current supply and a pair of output terminals for connection across the lamp. A ballast inductor is connected at its ends in series between one of the input terminals and one of the output terminals. A pulse generator is connected between one of the input terminals and one of the output terminals and another pulse generator is connected between a tapping point on the ballast inductor and the outer input terminal or the other output terminal or a point on the connection therebetween. The high voltage pulse generator includes a non-linear capacitor (NLC) and a semiconductor bipolar thyristor (commonly known as SIDAC) connected in series, the non-linear capacitor and the bipolar thyristor being connected in parallel with the lamp.