【单选题】
35在由PNP晶体管组成的基本共射放大电路中，当输入信号为1KHz、5mV的正弦电压时，输出电压波形出现了顶部削平的失真。这种失真是___ 。
A. 饱和失真
B. 截止失真
C. 交越失真
D. 频率失真
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相关试题
【单选题】
36在由PNP晶体管组成的基本共射放大电路中，当输入信号为1KHz、5mV的正弦电压时，输出电压波形出现了底部削平的失真。这种失真是___ 。
A. 饱和失真
B. 截止失真
C. 交越失真
D. 频率失真
【单选题】
37共集电极放大电路中Re的负反馈组态是___。
A. 电压串联负反馈
B. 电流串联负反馈
C. 电压并联负反馈
【单选题】
38为了使放大器带负载能力强，一般引入___负反馈。
【单选题】
41为了提高三极管放大电路的输入电阻，采用___负反馈 i=i1+i2
【单选题】
42为了稳定输出电流，采用___负反馈。
【单选题】
43为了改善放大器的动态性能，应该引入___电路。
A. 直流负反馈
B. 交流负反馈
C. 电压负反馈
D. 电流负反馈
【单选题】
44为了稳定放大器的静态工作点，应该引入___电路。
A. 直流负反馈
B. 交流负反馈
C. 电压负反馈
D. 电流负反馈
【单选题】
45共模抑制比是差分放大电路的一个主要技术指标，它反映放大电路___能力。
A. 放大差模抑制共模
B. 输入电阻高
C. 输出电阻低
【单选题】
46差分放大电路是为了___而设置的。
A. 稳定Au
B. 放大信号
C. 抑制零点漂移
【单选题】
47分析运放的“虚短”是指是___。
A. U-≈U+
B. I-≈I+≈0
C. U0=Ui
D. U-≈U+≈0
【单选题】
48分析运放的“虚断”是指是___。
A. U-≈U+
B. I-≈I+≈0
C. I-≈I+
D. U-≈U+≈0
【单选题】
51两级放大电路，Au1=-40，Au2=-50，若输入电压U1=5mv，则输出电压Uo为 ___
A. -200mv；
B. -250mV；
C. 10V；
D. 100V
【单选题】
52通用型集成运放的输入级多采用___。
A. 共基接法
B. 共集接法
C. 共射接法
D. 差分接法
【单选题】
53理想运放的两个重要性质是___。
A. 虚短与虚地
B. 虚断与虚短
C. 断路与短路
【单选题】
54振荡器的输出信号最初由___而来的。
A. 基本放大器
B. 选频网络
C. 干扰或噪声信号
【单选题】
55产生正弦波自激震荡的稳定条件是___。
A. 引入正反馈
B. |AF|≥1
C. AF=1
【单选题】
56从结构上来看，正弦振荡电路是一个 ___ 。
A. 有输入信号的负反馈放大器；
B. 没有输入信号的带选频网络的正反馈放大器；
C. 没有输入信号的不带选频网络的正反馈放大器。
【单选题】
57对频率稳定度要求较高的振荡器，要采用： ___ 。
A. LC振荡电路；
B. RC振荡电路；
C. RL振荡电路；
D. 石英晶体振荡电路。
【单选题】
58在甲类、乙类、甲乙类放大电路中，其导通角分别为___
A. 小于180 O、180 O、360O
B. 360O、180 O、小于180 O。
C. 180 O、小于180 O、360O
【单选题】
W78XX系和列W79XX系列引脚对应关系为 ___ 。
A. 一致；
B. 1脚与3脚对调，2脚不变；
C. 1、2对调。
【单选题】
60两个β相同的晶体管组成复合管后，其电流放大系数约为 ___ 。
【单选题】
1三极管的开关特性是___。
A. 截止相当于开关接通
B. 放大相当于开关接通
C. 饱和相当于开关接通
D. 截止相当于开关断开，饱和相当于开关接通
【单选题】
2数字集成门电路，目前生产最多应用最普遍的门电路是___
【单选题】
3由一个三极管组成的基本门电路是___。
【单选题】
4在遥测系统中，需通过___把非电量的变化转变为电信号。
A. 电阻器、
B. 电容器、
C. 传感器、
D. 晶体管
【单选题】
5半导体发光数码管由___个条状的发光二极管组成。
【单选题】
6“有0出1，全1出0”属于___
A. 与逻辑
B. 或逻辑
C. 非逻辑
D. 与非逻辑
【单选题】
7二进制数11101转化成十进制数为___
【单选题】
8TTL系列集成芯片工作电源电压的典型值是___。
A. 18V
B. 5V
C. 3V
D. 10V
【单选题】
10以下表达式中符合逻辑运算法则的是___。
A. 1+1=10
B. A+A=2A
C. A+=1.
D. A·=1
【单选题】
11对于TTL与非门闲置输入端的处理，不可以___
A. 与有用输入端并联
B. 通过电阻3kΩ接电源
C. 接地
D. 接电源
【单选题】
12十线/四线优先编码器74LS147所用的输出代码为___。
A. 5421BCD码
B. 格雷码
C. 8421BCD码
D. 余3码
【单选题】
13为实现“线与”逻辑功能，应选用___
A. OC门
B. 与门
C. 异或门
D. 同或门
【单选题】
14和逻辑式A+ABC相等的式子是___
【单选题】
15逻辑函数的表示方法中具有唯一性的是___
A. 真值表
B. 表达式
C. 逻辑图
D. 卡诺图
【单选题】
16与模拟电路相比，数字电路主要的优点是___。
A. 容易设计
B. 通用性强
C. 抗干扰能力强
【单选题】
17某门电路的输入输出波形如图所示，试问此逻辑门的功能是___。
【单选题】
18以下电路中常用于总线应用的有___。
A. TSL门
B. OC门
C. 漏极开路门
D. CMOS与非门
【单选题】
逻辑表达式Y=AB可以用___实现。
A. 正或门
B. 正非门
C. 正与门
D. 负或门
推荐试题
【单选题】
党的领导地位和____不是与生俱来，也不是一劳永逸的。___
A. 执政地位
B. 首创地位
C. 国际地位
D. 社会地位
【单选题】
中国共产党要把______这场伟大的革命进行好，党必须进行自我革命，全面增强党的执政本领。 ___
A. 新时代经济体制改革
B. 新时代政治体制改革
C. 新时代坚持和发展中国特色社会主义
D. 新时代中国改革开放
【单选题】
中国特色社会主义道路是实现社会主义现代化、创造人民美好生活的______。___
A. 理论依据
B. 必由之路
C. 根本保障
D. 行动指南
【单选题】
确保党始终总揽全局、协调各方，必须____。___
A. 得民心者得天下
B. 坚持和完善党的领导的体制机制
C. 学习达国家的经验
D. 选举优秀领导人
【单选题】
增强面对新时代新使命,必须在全党营造善于学习、勇于实践的浓厚氛围，建设马克思主义____政党。 ___
A. 人民型
B. 事业型
C. 研究型
D. 学习型
【单选题】
必须坚持党的（ ），既要充分发扬民主，又要善于集中。 ___
A. 集中民主制
B. 民主集中制
C. 多党合作制
D. 全民民主制
【单选题】
党是最高政治领导力量，是推进伟大事业的（ ）保证。 ___
【单选题】
According to one study, what do green spaces do to people? ___
A. Improve their work efficiently.
B. Add to their sustained happiness.
C. Help them build a positive attitude towards life.
D. Lessen their concerns about material well-being.
【单选题】
What does Dr. White say people usually do to make themselves happier? ___
A. Earn more money.
B. Settle in an urban area.
C. Gain fame and popularity.
D. Live in a green environment.
【单选题】
What does Dr. White try to find out about living in a greener urban area? ___
A. How it affects different people.
B. How strong its positive effect is.
C. How long its positive effect lasts.
D. How it benefits people physically.
【单选题】
What did Dr. White’s research reveal about people living in a green environment? ___
A. Their stress was more apparent than real.
B. Their decisions required less deliberation.
C. Their memories were greatly strengthened.
D. Their communication with others improved.
【单选题】
According to Dr. White, what should the government do to build more green spaces in cities? ___
A. Find financial support.
B. Improve urban planning.
C. Involve local residents in the effort.
D. Raise public awareness of the issue.
【单选题】
The survey by the Kaiser Family Foundation is mentioned to illustrate the idea that . ___
A. kids don’t always follow parents’ rules
B. only few parents believe the good news
C. much media use results in bad health
D. parents’ rules make a huge difference
【单选题】
What did the kids do when parents set any time or content limits, according to the Kaiser Family Foundation? ___
A. They cut down on their screen time.
B. They appreciated their parents’ love.
C. They spent more time staying outdoor.
D. They accepted parents’ rules unwillingly.
【单选题】
What will Kenneth Ginsburg most probably suggest that parents should do? ___
A. Avoid setting firm rules.
B. Avoid ruling with an iron grip.
C. Set rules after family discussion.
D. Set rules that are easy to understand.
【单选题】
Margaret Broe -Fitzpatrick finds it impossible. ___
A. to achieve just- right parenting
B. to keep track of everything done by the kids
C. for the kids to face rules alone
D. for the kids to observe rules without protest
【单选题】
The passage is mainly intended for parents . ___
A. whose kids have difficulty in self- discipline
B. whose kids are addicted to media use
C. who have doubts about setting rules
D. who are too busy to care for their kids
【单选题】
The word “it” (Para. 2) most probably refers to. ___
A. the lack of stable communities
B. the breakdown of informal information channels
C. the increased mobility of families
D. the growing number of people moving from place to place
【单选题】
The main problem people may encounter today arises from the fact that . ___
A. they have to learn new things consciously
B. they lack the confidence of securing reliable and trustworthy information
C. they have difficulty obtaining the needed information readily
D. they can hardly carry out casual communications with an extended family
【单选题】
From the passage we can infer that _______. ___
A. electronic mail will soon play a dominant role in transmitting messages
B. it will become more difficult for people to keep secrets in an information era
C. people will spend less time holding meetings or conferences
D. events will be reported on the spot mainly through satellites
【单选题】
Technology facilitates _______. ___
A. sharing information
B. storing and sending information
C. providing people with easy access to more information
D. all of the above
【单选题】
We can learn from the last paragraph that _______. ___
A. it is necessary to obtain as much
B. people should make the best use of the information
C. we should realize the importance of accumulating information
D. it is of vital importance to acquire needed information efficiently
【单选题】
The author thinks that people are _________. ___
A. satisfied with their appearance
B. concerned about appearance in old age
C. far from neglecting what is in fashion
D. reluctant to follow the trends in fashion
【单选题】
Fashion magazines and TV advertisements seem to link fashion to _________. ___
A. confidence in life
B. personal dress
C. individual hair style
D. personal future
【单选题】
Causes of fashions are _________. ___
A. uniform
B. varied
C. unknown
D. inexplicable
【单选题】
Present-day society is much freer and easier because it emphasizes _________. ___
A. uniformity
B. formality
C. informality
D. individuality
【单选题】
Which is the main idea of the last paragraph? ______________ ___
A. Care about appearance in formal situations.
B. Fashion in formal and informal situations.
C. Ignoring appearance in informal situations.
D. Ignoring appearance in all situations.
【单选题】
Permissive parents would ________. ___
A. let their children read any books they like to
B. not let their children see any films they like to
C. not let their children read any books without first checking their contents
D. let their children see the films with their first checking
【单选题】
The fact that parents check the contents of the book or the film for their children to read or see shows __________. ___
A. the necessity of censorship
B. that many books and films are bad
C. that children need their parents to help them understand more
D. that the parents are permissive
【单选题】
Which of the following statements is NOT true?____________ ___
A. Some adults can’t tell right from wrong.
B. Censorship is compared to the law because both of them perform good service to society as a whole.
C. Censors pay attention only to genuine works of art.
D. Censorship is necessary because many books, plays and films are far from being “works of art”.
【单选题】
What does the word “corrupt” in Para.4 mean?__________ ___
A. Make morally bad.
B. Hurt.
C. Injure.
D. Damage.
【单选题】
What would be the best title of this passage?_____________ ___
A. Permissive Parents and Responsible Parents.
B. Censorship and the Law.
C. Censors Value Artistic Merits .
D. Censorship Performs Good Service to Society.
【单选题】
Lie detectors are widely used in the United States because _____________. ___
A. they can help detect people’s emotional stress
B. they can help detect people's physiological changes
C. they can help find out whether a person is telling the truth or not
D. they can measure the subject’s electrical resistance
【单选题】
According to the passage, we know that Britain______________. ___
A. will adopt lie detectors widely
B. will adopt lie detectors on a smaller scale
C. adopt lie detectors
D. has not decided whether to adopt lie detectors or not
【单选题】
The tests themselves are by no means free from error..." (Line 1-2.Para.3) means ____________. ___
A. the tests definitely have no error
B. the tests sometimes make mistakes
C. the polygraphers do not make mistakes
D. the polygraphers can avoid error by using some techniques
【单选题】
Which of the following is true? ________________ ___
A. The tests are conducted by qualified polygraphers.
B. Innocent people may blush or stammer when questioned.
C. Guilty people can definitely be found out by answer questions
D. Guilty people may escape by refusing to answer questions.
【单选题】
What troubles lie detector researchers most is that _______________. ___
A. innocent people are convicted crimes
B. innocent people will learn to tell lies
C. lie detectors may cause industrial unrests
D. lie detectors are sometimes not dependable
【单选题】
In the passage the author's attitude towards "mixed-ability teaching" is _______. ___
A. critical
B. questioning
C. approving
D. objective
【单选题】
By "held back" (Line 1) the author means _____. ___
A. made to remain in the same classes
B. forced to study in the lower classes
C. drawn to their studies
D. prevented from advancing
【单选题】
The author argues that a teacher's chief concern should be the development of the student's _________. ___
A. personal qualities and social skills
B. total personality
C. learning ability and communicative skills
D. intellectual ability
