Investigations of the audible noise of inductors with respect to different ferromagnetic materials

Fluorescent lamps are one of the most modern light sources. They can be connected to the 230Vac supply without a transformer. To operate them, an inductor and starter are required only. The main disadvantage of this type of light source is the emitted audible noise of a frequency of 100Hz. For this phenomenon the inductor is responsible. Electromagnetic forces and magnetostriction are acting on the body of the device causing the sound emission. Here, the audible noise problem is investigated with respect to different ferromagnetic materials and the range of applied flux densities inside the iron core.