Acoustic resonance characterization of low-wattage metal-halide lamps under low-frequency square-waveform operation

In this paper a study about acoustic resonance in low-wattage metal halide lamps is presented. The lamps are supplied with a low frequency square waveform on which a high frequency sinusoidal ripple waveform is superposed. The goal is to emulate the same current waveform produced by low frequency electronic ballasts. In this way, the acoustic resonances appearing in the lamp can be characterized against ripple amplitude and frequency. Different lamp´s manufacturers and aging periods are used. The obtained results are intended to be employed in further reliable designs of low frequency electronic ballasts.