洗衣机定时控制器的设计.doc

目 录 1 选题背景......................................................1 1．1 指导思想.................................................................1 1．2 方案论证.................................................................1 1．3 基本设计任务............................................................1 1．4 发挥设计任务............................................................1 1．5电路特点..................................................................1 2 电路设计..........................................................................2 2.1 总体方框图...............................................................2 2.2 工作原理................................................2 3 各主要电路及部件工作原理....................................................3 3.1 555单稳态触发电路.....................................................3 3.2 74LS192简要说..........................................................3 3.3 一百进制分计数器和六十秒计数器的设计....................4 3.4 时间设置电路设计........................................6 3.5 状态显示电路............................................6 3.6 时间显示电路设计........................................7 3.7 报警电路设计............................................8 4 原理总图..........................................................................9 5 元器件清单.......................................................................9 6 调试过程及仿真结果...........................................................10 6.1 通电前检查..............................................................10 6.2 通电检查................................................................10 6.2.1复位开关的检查.................................................10 6.2.2 NE555单元电路调试............................................10 6.2.3发光二极管及三极管调试......................................10 6.3 结果分析...............................................10 7 小结..............................................................................11 8 设计体会及今后的改进意见...................................................11 8.1 体会...................................................11 8.2 本方案特点及存在的问题.....................