Variation of the instantaneous luminous flux of fluorescent lamps fed by dimmable electronic ballasts with frequency control

Effects of hysteresis and inertial processes on the instantaneous luminous flux of fluorescent lamps (FLs) are experimentally investigated, which are fed by frequency controlled, dimmable, electronic ballasts. Other phenomena are also examined, such as the time displacement between the light ripple and the waveform of the electrical power of the lamp, the ´modulation´ of the instantaneous luminous flux waveform and generally, the behaviour of the lamp at varying high frequency (HF) levels. For a typical FL, fed by dimmable electronic ballast with frequency control, inertial processes are reduced, as the operating frequency of the lamp decreases. The time displacement between the instantaneous luminous flux and the lamp power has maximal and minimal as frequency varies. As frequency of the FL increases, the diffusion of the metastable states of the Hg atoms is enhanced and the ´modulation´ of the instantaneous luminous flux decreases. The hysteresis and the looping of lamp´s voltage-current and luminous flux- current characteristics at various frequency levels indicate that it is necessary to add an inductance and a capacitance to the equivalent electrical circuit of a FL at HFs.