Investigation on methods of eliminating acoustic resonance in small wattage high-intensity-discharge (HID) lamps

In this paper, a detailed theoretical prediction and experimental verification of acoustic resonance frequency distribution in a small wattage metal-halide (MH) lamp is presented. Extensive experiments have been conducted on 35 W MH lamps to investigate different methods for avoiding acoustic resonance. The results indicate that a randomized switching scheme cannot eliminate arc instabilities caused by acoustic resonances in small wattage MH lamps. A stable arc can be obtained when the lamp is operated above the highest acoustic resonance frequency.