voltage charged in the capacitor into alternating voltage and itself adapts the voltage according to a fluorescent tube 4 typically electronic ballasts generate voltage having a frequency ranging between 20 100 khz for a lamp feeding appropriate alternating currents both to the cathodes of the tube and to the tube itself in fig1 and 2 current is fed into the lamps in the lamp circuit through an inductive coupling using a transformer coupling 5 at its simplest the control signal p transmitted by the control filter 1 is a voltage level which may vary e g from one to ten volts this voltage level is then interpreted in the ballast in a manner known per se and a chopper type dc ac converter converts its modulation on account of the signal to generate appropriate voltages to the lamp circuit both for the cathodes and the tube thus controlling the luminosity obtained from the tube such an embodiment reacting to the voltage signal is known per se from solutions wherein a separate control signal is conveyed to the ballast through a separate control wire according to a preferred embodiment of the invention the power filter part comprises a chopper circuit for.