| 摘要 |
<p>PURPOSE:To suppress the generation of noise when an electric discharge lamp is turned ON, by setting a frequency which reaches a maximum peak level among vibrations generated from a ballast element so that said frequency is a specific number of times as high as the intunsic frequency of the ballast main body. CONSTITUTION:A ballst element 1 is formed by winding a coil on an iron core 2, and a choke coil or a leakage transformer 4 is generally employed as the element 1. The transformer 4 is accommodated in a casing 5, together with a capacitor 6. A filling material 7 is filled in the space between the tranformer 4, the capacitor 6 and the casing 5. Thus, a ballast main body 8 having the element 1 incorporated in the casing 5 is formed. In the main body 8 having such arrangement, a frequency which reaches a maximum peak level among vibrations generated from the element 1 when the electric discharge lamp is turned ON is set so as to be at least 1.4 times as high as the natural vibration frequency of the main body 8. Thus, the occurrence of resonance between the main body 8 and the vibration generated from the element 1 is prevented, and the generation of large noise is thereby prevented when the electric discharge lamp is turned ON.</p> |
