24秒倒计时牌

24秒倒计时牌 1 设计 领导形象设计圆作业设计ao工艺污水处理厂设计附属工程施工组织设计清扫机器人结构设计 任务描述 1.1 设计 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 目:24秒倒计时牌 1.2 设计要求 1.2.1 设计目的 (1)掌握24秒倒计时牌的组装 方法 快递客服问题件处理详细方法山木方法pdf计算方法pdf华与华方法下载八字理论方法下载 与技巧; (2)掌握元器件的实现功能与使用; (3)能够通过对元器件组装来实现各种功能的电路; 1.2.2 基本要求 (1) 可手动暂停,还原; (2) 到0时有长报警,到倒数5秒时每秒有一声短报警; (3) 可显示计数，每过十秒有一次闪烁; 1.2.3 发挥部分 (1)24秒可调; of vision Yibin formation in the Center surrounded by, organic dispersion band of bead-space layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a long-term basis in a reasonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multi-center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and connotation type upgrade simultaneously of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space and protection of historical 2 设计思路 24秒倒计时器牌的核心部分是倒计时部分，我选择了两个74HC290连级来实现，因为它有置数端和预置端，可完成可调的倒计时器。本次设计有基本要求:可手动暂停、还原;每十秒显示器闪烁一次;到倒数5秒时每秒有一声短报警，到0秒时是长报警，发挥部分是24秒可调。 首先是要给计时器提供一个秒脉冲发生器，由于555定时器内部的比较器灵敏度非常高，输出驱动电流大，功能灵活，而且采用差分电路形式，用555定时器组成的多谐振荡器的振荡频率手电源电压和温度变化的影响很小，因此采用555定时器来提供发生脉冲。 手动暂停还原中，由于需要暂时锁住显示器显示的数，所以可以在秒脉冲的输出端加一个开关，当要计数时关闭开关进行计数，需要暂停时断开开关终止秒脉冲的输入，即可实现手动暂停还原此时显示器保持原来的数字。 每十秒显示器闪烁一次，若想有闪烁效果需要给需要给显示器提供5~10赫兹的脉冲信号才能有闪烁效果，只要当个位为“0000”时闪烁即为每十秒闪烁一次，通过各种门电路把“0000”的信号与5~10赫兹的脉冲信号共同作用提供给显示器。 到5秒时开始每秒都有一次短报警，到0秒时是长报警，则十位输出是“0000”，5秒时个位的最高位也为零，使个位输出“101”、“100”、“011”、“010”、“001”时有效列真值表，通过门来连接;当为“000”时，为长报警。给短报警一个500赫兹的脉冲信号，给长报警一个1000赫兹的脉冲信号，再通过一个或门来控制输出那个报警信号提供给报警电路。 24秒可调，在74HC192的预置端加入开关来调节想要预置的秒数。 -otection of historicaland prservice capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead 2 - 24秒倒计时牌 3设计方框图 十位 个位 显示器 显示器 信号发 生器 译码驱动译码驱动 部分 部分 短报警 倒计时器 倒计时器 长报警 置数 暂停与启动 信号发 生器 秒脉冲信号 十分频 二分频 十秒闪烁 十分频 信号发 十分频 生器 -ction of urban green space system, promoting the construction of peripheral green space and protection of historicaleatures, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construcity flayout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable otation type upgrade simultaneously of mode, in Metro construction of center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-rban district along the Yangtze River in Yibin "Ribbon multiterm basis in a reasonable space to develop, perfect u-t; the South Bank area, the minjiang River area, Golden Sands area on a longnd, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the Weson to expaspace layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new visi-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead 3 - 4 各部分电路设计及参数计算 4.1秒脉冲发生装置 输出1赫兹 通过555定时器来实现输出1000赫兹的脉冲信号发生源，为得到1赫兹的秒脉冲信号，用三个十分频来实现， 74290N是一种能实现是分频的非常简易芯 片。 此555定时器频率为1000赫兹，60%占空比，即高电平站一个周期的十分之八。555定时器组件工作在自激震荡状态。其振荡频率与定时元件的关系如下: f=1/T=1.43/(R+2R) (4.1) 12 选择定时电容值为10nF，且带入f,1000Hz，可求得: 5 R+2R=1.43×10(4.2)12 高占空比为DH= (R+R)/(R+2R) (4.3) 1212 低占空比为DL= R/(R+2R) (4.4) 212 现要求DH=0.6，DL=0.4，能确定R与R的关系进而求出 12 R1=28.86K?，R2=57.72 K? otection of historicaland prservice capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead- 4 - 24秒倒计时牌 4.2 到0时有长报警,到倒数5秒时每秒有一声短报警电路设计 layout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable otation type upgrade simultaneously of mode, in Metro construction of center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-rban district along the Yangtze River in Yibin "Ribbon multiterm basis in a reasonable space to develop, perfect u-t; the South Bank area, the minjiang River area, Golden Sands area on a longnd, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the Weson to expaspace layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new visi-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead-ction of urban green space system, promoting the construction of peripheral green space and protection of historicaleatures, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construcity f 5 - 长报警 短报警 输入1赫兹 秒脉冲 此部分是通过各种门来实现长报警与短警的。到0时有长报警,到倒数5 -otection of historicaland prservice capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead 6 - 24秒倒计时牌 秒时每秒有一声短报警，它们的共同部分是十位为“0000”，并且个位的最高位为了“0”在一起组成一个固定输出端。列真值表: 表4.3真值表 QC QB QA L 0 0 0 0 0 0 1 1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 1 1 1 1 0 0 1 1 1 0 _ _ _ _ _ _ _ _ L= QQQ+ QQQ+QQQ+QQQ+QQQC B AC B AC B AC B AC B A _ _ _ = QQ +QQ +QQC BC BB A 通过非门、与门、或非门来连接实现1秒到5秒有效。在零秒时，“000”时用一个或非门(三个输入端、一个输出端)实现，再把这两个不同的输出信号与前述的固定端分别用与门连接，给短报警一个500赫兹的脉冲信号，给长报警一个1000赫兹的脉冲信号，再通过一个或门来控制输出那个报警信号提供给报警电路。 4.3信号发生装置 5V5V1000赫兹VsVs500赫兹 1319脉冲信号 脉冲信号 57.72kΩ28.86kΩVCCVCCR1R12829RSTOUTRSTOUT2027DISDIS THRTHR4548100Ω100ΩTRITRI115.4kΩ57.72kΩRlRlCONCONR2R24649GNDGND 555_VIRTUAL555_VIRTUAL TimerTimer10nF10nF10nF10nF CCfCCf 00 (A) (B) 用555定时器芯片组成的多谐振荡器如图(A)(B):其中R相当一个定时2电阻决定C的放电的持续时间，起始时，电容C上电压V因放电而下降，当其C while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable otation type upgrade simultaneously of mode, in Metro construction of center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-rban district along the Yangtze River in Yibin "Ribbon multiterm basis in a reasonable space to develop, perfect u-t; the South Bank area, the minjiang River area, Golden Sands area on a longnd, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the Weson to expaspace layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new visi-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead-ction of urban green space system, promoting the construction of peripheral green space and protection of historicaleatures, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construcity flayout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping 7 - 值低于下阈值1/3V时定时器被触发端触，输转换为高电平，释放电晶体管截止。CC 电容C开始充电，以(R，R)C的常数趋向V。当电容上电压V上升到上阈值,2CCC2/3V时，输出又转换为低电平，并使放电晶体管导电。电容C又重新通过R和CC2放电晶体管放电，近似以RC的时常数趋向于零。当电容C上电压下降到1/3V2CC时，开始新的循环。如此反复，定时器连续震荡，在输出端产生矩形脉冲在电容C上形成近似锯齿波的波形。 根据上述分析，利用电路暂态分析的三要素法，得电容C充电的电压表为 -t/τV=1/3V+2/3V(1) (4.4-e)式中， CCCCC τ =(R+R)C (4.5) 12 t=t时V =V ，充电结束。 pHCCC -t/(R1，R2)C即:V=2/3V=1/3V+2/3V(1-e) (4.6)从上式中可求得 CCCCCCC t=(R+R)C ln2=0.7(R+R) C=0.7(R+R)C (4.7) pH 121212 -t/ R2C同理可求得C放电的电压表示为 V=2/3V e， t=t时，V=1/3V，CCCpLCCC， -t/ R2C 放电结束，从式V=2/3V e(4.8) CCC -t/ R2C可得V=1/3V=2/3V e (4.9) CCCCC t=τln20.7R(4.10) pL2 振荡周期为 T=t+t=0.7( R，2R)C (4.11) pH pL,2 振荡频率为 f=1/T=1.43/(R+R)C (4.12) 12 v c 2 VCC3 1VCC3 0 t vo t pHtpL 0 t T 图4.3工作波形 4.4分频电路 service capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead-otection of historicaland pr 8 - 24秒倒计时牌 信号发生器 输出1赫兹 脉冲信号 图4.4分频电路 在数字逻辑电路中，脉冲分频器通常采用计数式分频电路。计数器本身就可以作为分频器，用作分频器的计数器，主要关心的不是计数器则采用什么码型，计数器处于什么状态，也不需要译码显示等等。作为分频器，考虑的是输出脉冲与输入脉冲的重复频率之间存在什么关系，即电路的分频系数是多少，以及输出脉冲是不是对称方波等分频系数为整数的分频器，其输入脉冲一般是周期性脉冲，如果要求分频器的输出脉冲为对称方波，则要求输入脉冲必须是对称方波。 由于信号发生器提供的是1000赫兹的脉冲信号，使用了3个74290N来进行三次十分频是输出为1赫兹的脉冲信号。按照8421BCD码进行加法计数的74290N提供了两个复位控制端置0、置9，能通过多种方式实现十进制计数。 4.5报警发生装置 eatures, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construcity flayout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable otation type upgrade simultaneously of mode, in Metro construction of center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-rban district along the Yangtze River in Yibin "Ribbon multiterm basis in a reasonable space to develop, perfect u-t; the South Bank area, the minjiang River area, Golden Sands area on a longnd, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the Weson to expaspace layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new visi-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead-ction of urban green space system, promoting the construction of peripheral green space and protection of historical 9 - 输入500赫兹、 1000赫兹的脉冲 信号 如上(A)(B)图:555定时器芯片可拓展到不同的实际应用:按键去抖动 电路;延迟驱动器;漏脉冲检测器;可编程的定时器;分频器;压控振荡器;频 率计;玩具器件;电灯调光器;亮/暗检测器;红外线发射/接收器;开关电源时 钟电路，在这里信号发生器用555定时器芯片来提供 5工作过程分析 24秒倒计时器的主体部分是倒计时功能，通过对这次课程设计的基本要求 otection of historicaland prservice capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead- 10 - 24秒倒计时牌 首先选择了74LS192N，因为它不仅能进行加法减法的可逆运算，还有置零端和置数端为后续设计提供了良好的条件其余的部分为补助与补充部分，计数器的动力来源是秒脉冲信号利用555定时器来实现，由他产生1000赫兹的脉冲再通过三个十分频达到秒脉冲信号的实现，分频器一般分为三类，分频系数为整数，输出脉冲不是对称方波而是矩形波的分频器;分频系数为整数，输出脉冲为对称方波的分频器;分频系数为非整数，输出脉冲肯定不是方波而是矩形波的分频器。其中的报警、闪烁要通过计算来细心地设计组装成呢不过达到基本要求的电路。 报警电路中要识别5秒、0秒的电路特性，因为只与计数器的输出信号有关，可以计算来用各种非门、与门、或门、与非门、或非门来连接完成。闪烁部分由555定时器来1000赫兹的脉冲再通过二个十分频达到10赫兹再由一个二分频来实现5赫兹的脉冲来实现闪烁，由于74HC4511又熄灭功能因而能实现闪烁的效果，在提供提个触发器当个微为零时是译码器实现功能。当把倒计时器的预置开关调到“0010”“0100” 就可使预置端为24，再通过加入一个开关实现暂停功能。 ction of urban green space system, promoting the construction of peripheral green space and protection of historicaleatures, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construcity flayout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable otation type upgrade simultaneously of mode, in Metro construction of center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-rban district along the Yangtze River in Yibin "Ribbon multiterm basis in a reasonable space to develop, perfect u-t; the South Bank area, the minjiang River area, Golden Sands area on a longnd, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the Weson to expaspace layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new visi-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead- 11 - 6元器件清单 序号 元件名称 规格及用途 数量 1 定时器 555VIRTUAL-YIMER 3 2 倒计数器 74LS192N 2 3 计数器 74LS290N 3 4 译码显示器 74HC4511 2 5 或非门 74HC27N-6V 5 6 与门 74LS18D 9 7 与非门 74LS03N 2 8 非门 74HC05N-6V 4 9 D触发器 74LS74 3 ,10 电阻 28.86k 3 ,11 电阻 57.72k 4 ,12 电阻 115.4k 1 13 电容 PB-DPST 8 ,14 电阻 100 4 15 单刀双掷开关 STDP-OPEN 9 7主要原器件介绍 -otection of historicaland prservice capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead 12 - 24秒倒计时牌 7.1 计数器 74LS192N 7.1.1引脚图 U5 153AQA12BQB106CQC97DQD 1113~LOAD~BO1412CLR~CO 5UP4DOWN 74LS192N 7.1.2 功能表 DOWNCR UP DDDDQ Q Q Q 3210LD3210 1 × × × × × × × 0 0 0 0 0 0 × × DDDDDDDD321032100 1 1 × × × × 增计时 0 1 1 × × × × 减计时 0 1 1 1 × × × × 保持 7.1.3功能介绍 -ction of urban green space system, promoting the construction of peripheral green space and protection of historicaleatures, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construcity flayout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable otation type upgrade simultaneously of mode, in Metro construction of center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-rban district along the Yangtze River in Yibin "Ribbon multiterm basis in a reasonable space to develop, perfect u-t; the South Bank area, the minjiang River area, Golden Sands area on a longnd, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the Weson to expaspace layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new visi-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead 13 - UPDOWN可逆计数器74LS192是双时钟方式的。由，两管脚控制加减计数，上升沿触发，LD为预置输入控制端，CR为复位输入端CO为进位，BO为借位 CLRTCU输出，CPD为减计数时钟输入端有异步置数端和异步复位端，LOAD TCD和分别输出高电平表示加进位和减进位。 7.2 计数器74LS290N 7.2.1 引脚图 U2 109INAQA115INBQB4QC128R01QD13R02 1R913R92 74290N 7.2.2 功能表 复位输入 置位输入 时钟 输出 R0(1) R0(2) R9(1) R9(2) INB INA Q Q Q Q ABCD H H × × × L L L L L H H × × × L L L L L × × H H × H H L L H × × L × 计数 × L × L 计数 × L L × 计数 L × × L 计数 7.2.3 功能介绍 74HC290连级来实现，因为它有置数端和预置端，是常用的二,五,十进制异 Q步计数器，做八进制的就先把74LS290N接成十进制的INB与接，以INA做输A Q入，做输出就是十进制的。以从0000计到0111为例:先接成加法计数状态，C Q从上图中的74LS290N功能表把输出接到R01和R02脚上(即异步置0)，这D and prservice capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead-otection of historical 14 - 24秒倒计时牌 个时候当计数到1000时则立刻置0，重新从0开始计。 7.3 555定时器 7.3.1 管脚图 VCC RSTOUT DIS THR555_VIRTUAL TimerTRI CON GND 7.3.2 功能表 输入 输出 阀值输入 触发输入 复位 输出 放电管T ，，0 0 导通 12Vcc >Vcc 1 0 导通 33 12Vcc 1 不变 不变 33 7.3.3功能介绍 接通电源后，VCC经R1 R2给电容C充电。由于电容上电压不能突变，电源刚接通时VC 报告 软件系统测试报告下载sgs报告如何下载关于路面塌陷情况报告535n,sgs报告怎么下载竣工报告下载 时，我们所受的累都是值得的。 一周的课程设计就这样匆匆过去了，我们收获的是知识，收藏的是记忆，这次课程设计遇到的困难可能不及我们人生道路上所会遇到困难的万分之一，因此把这些挫折积攒起来将会终身受用，继续努力攀过眼前的一座座高峰，这次课程设计也是锦囊中的一个值得珍惜的回忆～ 参考文献 eatures, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construcity flayout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable otation type upgrade simultaneously of mode, in Metro construction of center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-rban district along the Yangtze River in Yibin "Ribbon multiterm basis in a reasonable space to develop, perfect u-t; the South Bank area, the minjiang River area, Golden Sands area on a longnd, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the Weson to expaspace layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new visi-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead-ction of urban green space system, promoting the construction of peripheral green space and protection of historical 19 - [1] 荀殿栋.实用数字电路. 北京:电子工业出版社， 第一版1994 [2] 赵负图.数字逻辑集成电路 手册 华为质量管理手册 下载焊接手册下载团建手册下载团建手册下载ld手册下载 . 北京:化学工业出版社, 第一版2005 [3] 毕满清.电子技术试验与课程设计.北京:机械工业出版社, 第三版2006 [4] 胡锦.数字电路与逻辑设计. 北京:高等教育出版社, 第四版2004 [5] 张晓林.数字电路原理与设计实例解析. 北京:电子工业出版社,第一版2004 [6]www.ic21.com 附 录 A1 逻辑电路图 -otection of historicaland prservice capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead 20 - 24秒倒计时牌 附 录 A2 印刷电路板图 layout optimization city structure, improve city traffic operation efficiency; vigorously improved city environment, shaping while is committed to old city transformation and built district of perfect, through live and industry with to of reasonable otation type upgrade simultaneously of mode, in Metro construction of center" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-rban district along the Yangtze River in Yibin "Ribbon multiterm basis in a reasonable space to develop, perfect u-t; the South Bank area, the minjiang River area, Golden Sands area on a longnd, Naxi district to the North, the East open places to expand, Jiang an eastward connection, Ping Shan, radiation to the Weson to expaspace layout structure, as leading development of the city to the East along the Yangtze River. Shi Gu area, lingang new visi-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead-ction of urban green space system, promoting the construction of peripheral green space and protection of historicaleatures, upgrade city quality, play city of service function, formed has perfect modern service capacity of big city. Construcity f 21 - -otection of historicaland prservice capacity of big city. Construction of urban green space system, promoting the construction of peripheral green space oved city environment, shaping city features, upgrade city quality, play city of service function, formed has perfect modern y impre and industry with to of reasonable layout optimization city structure, improve city traffic operation efficiency; vigorouslly of mode, in Metro construction of while is committed to old city transformation and built district of perfect, through livotation type upgrade simultaneouscenter" strategic vision of space frame. Yibin Center City development construction steering extension type extended and conn-easonable space to develop, perfect urban district along the Yangtze River in Yibin "Ribbon multiterm basis in a r-tion, Ping Shan, radiation to the West; the South Bank area, the minjiang River area, Golden Sands area on a longi Gu area, lingang new vision to expand, Naxi district to the North, the East open places to expand, Jiang an eastward connecspace layout structure, as leading development of the city to the East along the Yangtze River. Sh-of vision Yibin formation in the Center surrounded by, organic dispersion band of bead 22 -