便携系统的革命继续向前快 速发展。更新、更小的蜂窝电话、笔记本电脑和ＰＤＡ不断地出现在市场上。 尽管很多的小型化是集成的结果，但仍然有一些功能需要用分立元件（如晶体管和整流器）。这是由尺寸、成本和功耗诸因素决定的。这些功能需要开发更小的微型封装。 Ｍｏｔｏｒ The revolution in portable systems continues to move forward fast. Newer, smaller cellular phones, laptops and PDAs continue to appear on the market. Although many miniaturization are the result of integration, there are still some features that require discrete components (such as transistors and rectifiers). This is determined by factors such as size, cost and power consumption. These features require the development of smaller miniature packages. Motor