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并封鎖輸入編碼電路,禁止選手超時(shí)后搶答,時(shí)間顯示器顯示 0 三、進(jìn)度安排 設(shè)計(jì)時(shí)間為兩周,第一周查資料、方案論證,完成數(shù)字搶答器電路設(shè)計(jì),對(duì)元器件進(jìn)行篩選,第二周組裝、調(diào)試,進(jìn)行實(shí)物檢查、設(shè)計(jì)答辯并完成設(shè)計(jì)報(bào)告。 四、 摘要 中文摘要: 本文介紹了一種采用數(shù)字電路制作的多功能數(shù)顯搶答器,它主要采用了 74 系列的常用集成電路,它除了具有基本的搶答功能之外,還具有定時(shí)報(bào)警的功能,和數(shù)顯的功能,當(dāng)搶答開(kāi)始后,系統(tǒng)會(huì)自動(dòng)倒計(jì)時(shí),并且時(shí)間是可以預(yù)設(shè)的 ,期間有人搶答的話系統(tǒng)會(huì)停止計(jì)時(shí),如果期間沒(méi)人搶答,系統(tǒng)會(huì)有短暫的報(bào)警,提示搶答結(jié)束。 關(guān)鍵字 : PLC、搶答、報(bào)警、數(shù)顯 英文摘要 Abstract: This paper introduces a kind of adopting digital circuit made 2 multifunction digital display responder, it mainly adopts the 74 series of mon integrated circuit, it not only has basic vies to answer first function, but also has the timing alarm function, and digital display function, when vies to answer first began, the system will automatically count down, and the time can be preset, someone vies to answer first words during the system will stop time, if no one during the contest, the system will have a short warning and prompt vies to answer first end key words: microputer PLC 、 vies to answer first、 alarm、 digital display 五、系統(tǒng)框圖 當(dāng)主持人宣布開(kāi)始,定時(shí)電路開(kāi)始秒脈沖電路的作用而進(jìn)行倒記時(shí),并通過(guò)譯碼器在顯示器中顯示。報(bào)警電路給出聲音提示。當(dāng)選手首先按某一開(kāi)關(guān)鍵時(shí),可通過(guò)觸發(fā)鎖存電路被觸發(fā)并鎖存,在輸出端產(chǎn)生相應(yīng)的開(kāi)關(guān)電平信息,同時(shí)為防止其它開(kāi)關(guān)隨后觸發(fā)而產(chǎn)生紊亂,最先產(chǎn)生的輸出電平變化又反過(guò)來(lái)將觸發(fā)電路鎖定。然后在譯碼器中譯碼,將觸發(fā)器輸出的數(shù)據(jù) 轉(zhuǎn)換為數(shù)碼管需要的邏輯狀態(tài)。最后在顯示電路中顯示出所按鍵選手的號(hào)碼。若有多個(gè)開(kāi)關(guān)同時(shí)按下時(shí),則在它們之間存