设计并制作一个14键单音电子琴预先存入一些曲谱电路在4Hz的时钟控制下自动播放 通过220V电源适配器给电路提供工作电源-Design and production of a 14-key electric piano tone into a number of music scores advance in 4Hz clock circuit under the control of automatic play through 220V power adapter to provide