| 摘要 |
PURPOSE:To increase the variation of the oscillation frequency and thus to enhance the efficiency by using the noncrystal magnetic substance featuring large surface unevenness with the thickness of several tens of mu for the diaphragm of the sound generating substance. CONSTITUTION:The noncrystal magnetic substance is used for the sound generating substance. In this case, the thickness of the magnetic substance has about 20% variation, and this thickness features a gentle distribution over the entire diaphragm. Owing to the big unevenness, the curve (2) of the diaphragm and at the resonance time becomes borader than the curve (2) of the permalloy plate. Furthermore, the sound generation frequency produces a rasping sound containing a large amount of the higher harmonic component, which is more suited for the alarm tone. The noncrystal magnetic substance of just 20mu or so will do enough since it features a high degree of the springiness and hardness. And the thinner the more effective, and thus the noncrystal magnetic substance of 20-50mu thickness is used for diaphragm 1. |
