【正文】 ......................................................3 電路清零功能的設(shè)計(jì) ........................................................................................................................4 ................................................................................................................5 譯碼驅(qū)動(dòng)及顯示單元 ........................................................................................................................6 .............................................................................................................................6 第三章 . 元器件介紹 ....................................................................................................................................8 元器件清單 .........................................................................................................................................8 元器件介紹 .........................................................................................................................................8 555定時(shí) 器 .................................................................................................................................8 .........................................................................................................................9 一．相關(guān)設(shè)計(jì)方案及抉擇 ......................................................................................................................11 ................................................................................................................................................11 ................................................................................................................................................11 2．理論設(shè)計(jì) 單元電路與總電路設(shè)計(jì) .................................................................................................. 13 5V電壓源電路設(shè)計(jì) ............................................................................................................................ 13 降壓電路 ........................................................................................................................................ 13 1S信號源設(shè)計(jì)： ........................................................................................................................... 14 計(jì)數(shù)器電路設(shè)計(jì)： ......................................................................................................................... 16 74ls190管腳圖及功能簡介 ............................................................................................... 16 電路連接概述 ....................................................................................................................... 18 顯示電路 ........................................................................................................................................ 19 報(bào)警電路 ........................................................................................................................................... 21 控制電路 .......................................................................................................................................... 22 3．仿真調(diào)試 ................................................................................................................................................ 23 軟件介紹 ........................................................................................................................................ 23 調(diào)試過程 .......................................................................................................................................... 23 倒計(jì)時(shí)及停止電路調(diào)試 ........................................................................................................ 23 4．實(shí)驗(yàn)中出現(xiàn)的問題及解決方法 .......................................................................................................... 25 附錄 ............................................................................................................................................................... 27 電子秒表總電路圖 ...................................................................................................................................... 27 總體電路圖 .............................................................................................................................................. 27 元器件清單 ......................................