相关试题
【单选题】
当PNP型晶体管工作在放大区时，各极电位关系为uC ___uB。
【单选题】
32当PNP型晶体管工作在放大区时，各极电位关系为uB___uE 。
【单选题】
33测得NPN型三极管上各电极对地电位分别为，，，说明此三极管处在___。
A. 放大区
B. 饱和区
C. 截止区
D. 反向击穿区
【单选题】
34若使三极管具有电流放大能力，必须满足的外部条件是___。
A. 发射结正偏、集电结正偏
B. 发射结反偏、集电结反偏
C. 发射结正偏、集电结反偏
D. 发射结反偏、集电结正偏
【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
【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___
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【单选题】
If you want to ___ the wood, cut it with the grain, not against it.
A. break
B. burn
C. split
D. divide
【单选题】
They have a stronger ___ of the importance of economic incentives.
A. appreciation
B. learning
C. conception
D. idea
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I believe I am capable of ___ the political consequences accurately.
A. guessing
B. betting
C. calculating
D. computing
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30 percent of reptiles, birds, and fish are currently ___ with extinction.
A. treated
B. threatened
C. danger
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Workers should occasionally walk around, ___ and avoid prolonged periods at the desk.
A. pull
B. lengthen
C. strain
D. stretch
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These companies often encounter many ___ impediments to investment.
A. invisible
B. edible
C. feasible
D. capable
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Running a kitchen ___a great deal of discipline and speed.
A. including
B. involving
C. involves
D. composes
【单选题】
He had an ___ at a restaurant in Greek Street at eight.
A. engagement
B. engage
C. contract
D. promise
【单选题】
I think I would have died of ___.
A. embarrass
B. embarrassing
C. embarrassed
D. embarrassment
【单选题】
He saw the publication of this book as an embarrassing invasion of his ___.
A. secret
B. privacy
C. private
D. piracy
【单选题】
The trade imbalance is likely to rise again in 2020. ___ a new set of policy actions will be required soon.
A.
B. ecause B. Nevertheless
C. Hence
D. Therefore
【单选题】
Stratford police refuse to comment ___ whether anyone has been arrested.
A. about
B. on
C. at
D. with
【单选题】
The world will be different, and we will have to be prepared to ___ to the change.
A. adopt
B. adapt
C. accustom
D. adept
【单选题】
The company has launched a campaign of television ___ and leaflets.
A. commercials
B. commences
C. commerce
D. commercialization
【单选题】
The general secretary may ___ the president at official ceremonies.
A. present
B. represent
C. representative
D. stand
【单选题】
He ___ her arms behind her back and clipped a pair of handcuffs on her wrists.
A. dragged
B. pulled
C. stretched
D. twisted
【单选题】
Suppose that when I come back in ten years’ time all these old houses ___ down.
A. will have been pulled
B. will have pulled
C. will be pulling
D. will be pulled
【单选题】
The picture exhibition bored me to death. I wish I ___ to it.
A. have not gone
B. did not go
C. had not gone
D. should not have gone
【单选题】
An investigation was made into the accident ___ fifty people were killed.
A. for that
B. where
C. when
D. in which
【单选题】
___ with the picture, Mary tore it to pieces.
A. Dissatisfying thoroughly
B. Being thoroughly dissatisfied
C. To dissatisfy thoroughly
D. To be thoroughly dissatisfied
【单选题】
She was so angry that she felt like ___ something at him.
A. to throw
B. to have thrown
C. throwing
D. having thrown
【单选题】
If you want to know the train schedule, please ___ at the booking office.
A. acquire
B. inquire
C. request
D. require
【单选题】
My brother’s plans are very ___; he wants to master English, French and Spanish before he is sixteen.
A. arbitrary
B. aggressive
C. ambitious
D. abundant
【单选题】
Housewives who do not go out to work often feel they are not working to their full ___.
A. capacity
B. strength
C. length
D. possibility
【单选题】
Water and air are ___ to human beings. We cannot live without them.
A. harbor
B. function
C. definite
D. essential
【单选题】
Our challenge is to ___ those voters and inspire them to join our cause.
A. motion
B. motive
C. motivate
D. motivation
【单选题】
Harper was a teacher by ___.
A. career
B. occupation
C. profession
D. vocation
【单选题】
The doctor gave me a chest X-ray and ___some medicine for me.
A. prescribed
B. floated
C. drugged
D. drifted
【单选题】
The list is arranged according to the ___ professions of the audience.
A. resolution
B. responsible
C. resource
D. respective
【单选题】
The government is trying to do something to ___ better understanding between the two countries.
A. raise
B. promote
C. heighten
D. increase
【单选题】
According to the American federal government, residents of Hawaii have the longest life ___ : 77.2 years.
A. rank
B. span
C. scale
D. scope
【单选题】
Because of the boring ___, we need to take a vacation every year.
A. routine
B. surgery
C. rifle
D. sake
【单选题】
The manager spoke highly of such ___ as loyalty, courage and truthfulness shown by his employees.
A. virtues
B. features
C. properties
D. characteristics
【单选题】
Throughout his life, Henry Moore ___ an interest in encouraging art in the city of Leeds.
A. contained
B. secured
C. reserved
D. maintained
【单选题】
The new trade agreement should ___ more rapid economic growth.
A. facilitate
B. help
C. assist
D. speed
【单选题】
The new plan is ___ and everybody present agrees with it.
A. appendix
B. adventurous
C. feasible
D. impractical
【单选题】
A peculiarly pointed chin is his most memorable facial ___.
A. mark
B. feature
C. trace
D. appearance
【单选题】
The plant ___particularly well in slightly harsher climes.
A. succeeds
B. shows
C. flourishes
D. fosters
【单选题】
This company provides a very good ___service for its products.
A. maintenance
B. merit B. philosophy D. pigeon
【单选题】
Everyone is encouraged to ___ food or clothing for those who suffered a great deal in the flood.
A. attribute
B. distribute
C. contribute
D. drift
