应该对我们很有用，常用器件选行表是个东西，一般常用的器件都有做介绍。当你参加电子设计大赛，或自己做项目会有用的。-We should be very useful, commonly used device selection, the table is a thing, commonly used in the device descr iption has to do. When you participate in Electronic Design Contest, or their projects will be used to do.