【单选题】
23以下式子中正确的是___
A. 1+A=A
B. A+A=1
C. A•A=1
D. A+AB=A
查看试卷,进入试卷练习
微信扫一扫,开始刷题
答案
D
解析
暂无解析
相关试题
【单选题】
在一个四变量逻辑函数中,___为最小项。
A.
B.
C.
D.
【单选题】
A+BC=___。
A. A+B
B. A+C
C. (A+B)(A+C)
D. B+C
【单选题】
26以下代码中为无权码的为___。
A. 5421BCD码
B. 8421BCD码
C. 余三码
【单选题】
一位十六进制数可以用___位二进制数来表示。
A. 4
B. 2
C. 1
D. 16
【单选题】
28十进制数25用8421BCD码表示为___。4位
A. 10 101
B. 0010 0101
C. 100101
D. 10101
【单选题】
29与十进制数(53.5)10不等值的数或代码为___。
A. (0101 0011.0101)8421BCD
B. (35.8)16
C. (110101.1)2
D. (60.4)8
【单选题】
30与八进制数(47.3)8等值的数为___
A. (100111.011)2
B. (97.3)16
C. (27.3 )16
D. (100111.11)2
【单选题】
31下列各型号中属于优先编码器是___。
A. 74LS85
B. 74LS138
C. 74LS148
D. 74LS48
【单选题】
七段数码显示器BS202是___。
A. 共阳极LED管
B. 共阴极LED管
C. 共阳极LCD管
D. 共阴极LCD管
【单选题】
33八输入端的编码器按二进制数编码时,其输出端的个数是___。
A. 2个
B. 3个
C. 4个
D. 8个
【单选题】
四输入的译码器,其输出端最多为___。
A. 4个
B. 8个
C. 10个
D. 16个
【单选题】
当74LS148的输入端按顺序输入11011101时,输出为___。
A. 101
B. 010
C. 001
D. 110
【单选题】
用三线-八线译码器74LS138和辅助门电路实现逻辑函数Y=a2+a1a2,应___。
A. 用与非门,Y=y0y1y4y5y6y7
B. 用与门,Y=y2y3
C. 用或门,Y=y2+y3
D. 用或门,Y=y0+y1+y4+y5+y6+y7
【单选题】
37时序逻辑电路中一定包含___。
A. 触发器
B. 组合逻辑电路
C. 移位寄存器
D. 译码器
【单选题】
仅具有置“0”和置“1”功能的触发器是___。
A. 基本RS触发器
B. 钟控RS触发器
C. D触发器
D. JK触发器
【单选题】
由与非门组成的基本RS触发器不允许输入的变量组合为___。
A. 00
B. 01
C. 10
D. 11
【单选题】
40仅具有保持和翻转功能的触发器是___。
A. JK触发器
B. T触发器
C. D触发器
D. T' 触发器
【单选题】
触发器由门电路构成,但它不同于门电路功能,主要特点是___。
A. 具有翻转功能
B. 具有保持功能
C. 具有记忆功能
【单选题】
TTL集成触发器直接置0端[]和直接置1端[]在触发器正常工作时应___。
A. =1,=0
B. =0,=1
C. 保持高电平“1”
D. 保持低电平“0”
【单选题】
按逻辑功能的不同,双稳态触发器可分为___。
A. RS、JK、D、T等
B. 主从型和维持阻塞型
C. TTL型和MOS型
D. 上述均包括
【单选题】
同步计数器和异步计数器比较,同步计数器的显著优点是___。
A. 工作速度高
B. 触发器利用率高
C. 电路简单
D. 不受时钟CP控制。
【单选题】
把一个五进制计数器与一个四进制计数器串联可得到___进制计数器。
A. 4
B. 5
C. 9
D. 20
【单选题】
下列逻辑电路中为时序逻辑电路的是___ 。
A. 变量译码器
B. 加法器
C. 数码寄存器
D. 数据选择器
【单选题】
47N个触发器可以构成最大计数长度{进制数}为___ 的计数器。
A. N
B. 2N
C. N2
D. 2N
【单选题】
N个触发器可以构成能寄存___位二进制数码的寄存器。
A. N-1
B. N
C. N+1
D. 2N
【单选题】
49五个D触发器构成环形计数器,其计数长度为___。
A. 5
B. 10
C. 25
D. 32
【单选题】
同步时序电路和异步时序电路比较,其差异在于后者___。
A. 没有触发器
B. 没有统一的时钟脉冲控制
C. 没有稳定状态
D. 输出只与内部状态有关
【单选题】
一位8421BCD码计数器至少需要___个触发器。
A. 3
B. 4
C. 5
D. 10
【单选题】
某电视机水平-垂直扫描发生器需要一个分频器将31500HZ的脉冲转换为60HZ的脉冲,欲构成此分频器至少需要___个触发器。
A. 10
B. 60
C. 525
D. 31500
【单选题】
555定时器属于___
A. 时序逻辑电路
B. 组合逻辑电路
C. 模拟电子电路
【单选题】
54多谐振荡器可产生 ___
A. 正弦波
B. 矩形脉冲
C. 三角波
D. 锯齿波
【单选题】
脉冲整形电路有___。
A. 多谐振荡器
B. 施密特触发器
C. 555定时器
【单选题】
56石英晶体多谐振荡器的突出优点是___ 。
A. 速度高
B. 电路简单
C. 振荡频率稳定
D. 输出波形边沿陡峭
【单选题】
TTL单定时器型号的最后几位数字为___。
A. 555
B. 556
C. 7555
D. 7556
【单选题】
555定时器不可以组成___。
A. 多谐振荡器
B. 单稳态触发器
C. 施密特触发器
D. JK触发器
【单选题】
59以下各电路中,___可以产生脉冲定时。
A. 多谐振荡器
B. 单稳态触发器
C. 施密特触发器
D. 石英晶体多谐振荡器
【单选题】
555定时电路端不用时,应当___。
A. 接高电平
B. 接低电平
C. 通过0.01µF的电容接地
D. 通过小于500Ω的电阻接地
【单选题】
89S51的内部程序存储器与数据存储器容量各为多少?___
A. 64KB、128B
B. 4KB、64KB
C. 4KB、128B
D. 8KB、256B
【单选题】
89S51比89C51多出了哪个功能?___
A. 存储器加倍
B. 具有WDT工能
C. 多了一个8位输入/输出端口
D. 多了一个串行口
【单选题】
6在DIP40封装的8×51芯片里,复位RESET引脚的引脚编号是什么?___
A. 9
B. 19
C. 29
D. 39
推荐试题
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional Studies[ ]that children who often take part in cooperative programs benefit a lot more than other children
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional They are such a(n) [ ] family- they must have been shocked when their son dyed(染) his hair pink,
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional Testing students by examinations has long been regarded as a reliable way to [ ]students'ability
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional Many power stations have been modernized to give off less pollution, or they were moved further away from the living areas in order to [ ] the damage,
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional Unemployment has come down slightly, but this does not [ ]the fact that it is still a major problem
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional Mr. Smith is not doing well; the doctor told us that several colds [ ]his health
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional The best way to deal with problems at home is to talk things out calmly and honestly and try to reach a(n) [ ]
【填空题】
open the door to,In advance,all at once,reap the benefits (of), make the most of,over time, get by, stand a chance (of),remind of, take pleasure in, Experts say our company is amazing in that sales have been increasing steadily [ ]
【填空题】
make it, with open arms ,strip off,keep back, free of/ from ,after all,straighten up, throw away After 10 years of full-time training, she has,finally [ ] as a professional dancer.
【填空题】
make it, with open arms ,strip off,keep back, free of/ from ,after all,straighten up, throw away [ ], what is the point in taking part in the competitive event if the result is only to prove how incompetent you are?,
【填空题】
make it, with open arms ,strip off,keep back, free of/ from ,after all,straighten up, throw away Redecorating the house is a challenging task. It's necessary to [ ] the wallpaper first.
【填空题】
make it, with open arms ,strip off,keep back, free of/ from ,after all,straighten up, throw away I never really had any problems with change. On the contrary, I welcome change [ ]
【填空题】
make it, with open arms ,strip off,keep back, free of/ from ,after all,straighten up, throw away A lot of what we [ ] is made from raw materials which are not renewable
【填空题】
make it, with open arms ,strip off,keep back, free of/ from ,after all,straighten up, throw away Megan and John realized that their house was too messy for a new baby, so they decided to [ ] their house before the baby was born
【填空题】
make it, with open arms ,strip off,keep back, free of/ from ,after all,straighten up, throw away Jennifer couldn't [ ] her tears when she saw the sick children at a new blood cancer center in Virginia
【填空题】
make it, with open arms ,strip off,keep back, free of/ from ,after all,straighten up, throw away We want to give all children a world [ ] violence
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile Fortunately, the accident didn't [ ] many people, for there was little traffic at that hour.
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile She[ ] her ambition of becoming a fashion designer after years of hard work
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile They kept on trying their best to develop their business, but in such [ ]market competition, they had no Idea if success would come along one day
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile As music plays an important role in our life, many music teachers and educators [ ] taking up a musical instrument at a young age
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile This rule should be entirely clear in the minds of everyone and should not be misunderstood under any [ ]
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile My daughter was shy; she was afraid to ask questions,[ ] to questions in class,or talk with other children
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile I got from him only a letter, which was put on my office desk; [ ] to the receipt of this letter I have never heard from him
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile The duties to provide services for children in need are not [ ] to the local social services department
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile We pray that all nations be [ ] and that all people around the world live in peace
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional It was reported the president had [ ]to fight If war was necessary,even if it meant destroying his chances of re-election
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional I had to [ ] one of my email accounts as it was filled with junk mail
【填空题】
controversial,assess, resolve,decrease,alter,abandon,indicate,undermine,compromise, conventional Darwin's theory of evolution remains[ ] partly because it challenges the religious belief that God created man
【填空题】
advocate,involve,confine,respond,subsequent ,distinct ,intense, fulfill,circumstance, reconcile He suggested a small but [ ] improvement on our former plan; I really appreciate it.
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in She held her hand above her eyes to [ ]them [ ] the sun so that she could see more clearly the man in front of her
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in The boy studied the signs for over an hour,but still could not [ ]them, so he turned to his teacher for help
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in They [ ] the developed countries to commit more money to protecting the environment
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in We will continue to care for those [ ] and work to establish a society that is generous and prosperous
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in Many people [ ]careers and raising kids so that they forget that their marriages also need to be taken good care of
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in My most favorite program is the one that deals with scientific subjects that ordinary people can [ ]
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in Finally, I would like to [ ]by saying that it has been a tremendous pleasure to work with you all
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in He is a person that you always [ ]when you need help.
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in This restaurant is very popular because it has some separate, smaller rooms [ ] families with small children
【填空题】
in sb. 's words,count on,make sense of ,reserve for, shield from,call on, sum up, relate to ,in need, be/ get caught up in Betty loves reading.[ ],“Reading is the most wonderful thing in the world.”
【填空题】
open the door to,In advance,all at once,reap the benefits (of), make the most of,over time, get by, stand a chance (of),remind of, take pleasure in, Every one of you has made a contribution and I [ ] knowledging what each of you has done to make this academic convention such a success.