【单选题】
LC 选频振荡电路,当电路频率等于谐振频率时,电路性质为___。
A. 电阻性
B. 感性
C. 容性
D. 纯电容性
查看试卷,进入试卷练习
微信扫一扫,开始刷题
答案
A
解析
暂无解析
相关试题
【单选题】
阻值为4Ω的电阻和容抗为3Ω的电容串联,总复数阻抗为___
A. 3+j4
B. 3-j4
C. 4+j3
D. 4-j3
【单选题】
电动势为10V,内阻为2Ω的电压源变换成电流源时,电流源的电流和内阻是___
A. 10A,2Ω
B. 20A,2Ω
C. 5A,2Ω
D. 2A,5Ω
【单选题】
电流为5A,内阻为2Ω的电流源变换成一个电压源时,电压源的电动势和内阻为___
A. 10V,2Ω
B. 2.5V,2Ω
C. 0.4V,2Ω
D. 4V,2Ω
【单选题】
额定电压都为220V的40W、60W、100W三灯泡串联在220V的电源中,它们的发热量由大到小排列为___
A. 100W 60W 40W
B. 40W 60W 100W
C. 100W 40W 60W
D. 60W 100W 40W
【单选题】
在正弦交流电的解析式i=ImSin(ωt +φ)中,φ表示___
A. 频率
B. 相位
C. 初相位
D. 相位差
【单选题】
正弦交流电压u=100Sin(628t + 600)V,它的最大值为___。
A. 100 V
B. 100 V
C. 60V
D. 628 V
【单选题】
能表示容性电路电压与电流关系的相量图是___。
A.
B.
C.
D.
【单选题】
如图判断同名端为___
A. a与c
B. a与 d
C. b与c
【单选题】
电路中___定律指出:流入任意一节点的电流必定等于流出该节点的电流。
A. 欧姆
B. 基尔霍夫电流
C. 楞次
D. 基尔霍夫电压
【单选题】
已知电源电压为12 V ,四只相同灯泡的工作电压都是6 V,要使灯泡都能正常工作,则灯泡应___
A. 全部串联
B. 两只并联后与另两只串联
C. 两两串联后再并联
D. 全部并联
【单选题】
用戴维南定理分析电路“入端电阻”时,应将内部的电流源___处理。
A. 作开路
B. 作短路
C. 不进行
【单选题】
任何一个含源二端网络都可以用一个适当的理想电压源与一电阻___来代替。
A. 串联
B. 并联
C. 串联或并联
D. 随意联接
【单选题】
用交流电流表测得交流电流10A,则电路中电流的最大值为___。
A. 10A
B. 14.1A
C. 20A
D. 70.7A
【单选题】
如右图所示电路中,已知各支路的电流I1=I2=10A, 则电路的总电流I为___。
A. 20A
B. 0 A
C. 14.1A
D. 50A
【单选题】
1杂质半导体中多数载流子的浓度取决于___
A. 温度
B. 杂质浓度
C. 电子空穴对数目
【单选题】
2在电场作用下,空穴与自由电子运动形成的电流方向___
A. 相同
B. 相反
【单选题】
3光敏二极管应在___下工作
A. 正向电压
B. 反向电压
【单选题】
4下列半导体材料哪一种的热敏性突出“导电性受温度影响最大”?___
A. 本征半导体
B. N型半导体质
C. P型半导体
【单选题】
5用万用表电阻挡检测某一个二极管时,发现其正、反电阻均近于1000KΩ,这说明该二极管是属于___。
A. 短路状态;
B. 完好状态;
C. 断路状态;
D. 极性搞错。
【单选题】
6稳压二极管是一个可逆击穿二极管,稳压时工作在___状态。
A. 正偏
B. 反偏 E、正向导通 F、截止
【单选题】
7三端集成稳压器CW7812的输出电压是___。
A. 12V
B. 5V
C. 9V
【单选题】
8三端集成稳压器CXX7805的输出电压是___
A. 5v
B. 9v
C. 12v
【单选题】
9一个平衡PN结,用导线将P区和N区连起来,而导线中___。
A. 有微弱电流
B. 无电流
C. 有瞬间微弱电流
【单选题】
10二极管两端正向电压大于___电压时,二极管才导通。
A. 击穿电压;
B. 死区;
C. 饱和。
【单选题】
11当温度升高时,二极管的反向饱和电流 ___ 。
A. 增大;
B. 减小;
C. 不变;
D. 无法判定。
【单选题】
12硅二极管的正向导通压降比锗二极管的___ 。
A. 大
B. 小
C. 相等
【单选题】
13三端集成稳压器 CW7906的输出电压是___
A. -12v
B. -9v
C. -6V
【单选题】
14稳压管的工作是利用伏安特性中的___。
A. 正向特性
B. 反向特性
C. 反向击穿特性
【单选题】
15二极管具有___
A. 正向特性
B. 反向特性
C. 单向导电特性
D. 反向击穿特性
【单选题】
16图中D1-D3为理想二极管,A,B,C灯都相同,试问___灯最亮。
A. A灯
B. B灯
C. C灯
【单选题】
18在单相桥式整流电容滤波电路中,设U2为其输入电压,输出电压的平均值约为___。
A. U0=0.45U2
B. U0=1.2U2
C. U0=0.9U2
D. U0=1.4U2
【单选题】
19在单相桥式整流电路中,设U2为其输入电压,输出电压的平均值约为___。
A. U0=0.45U2
B. U0=1.2U2
C. U0=0.9U2
D. U0=1.4U2
【单选题】
20在半波整流电容滤波电路中,设U2为其输入电压,输出电压的平均值约为___。
A. U0=0.45U2
B. U0=1.2U2
C. U0=0.9U2
D. U0=1.4U2
【单选题】
21在半波整流电路中,设U2为其输入电压,输出电压的平均值约为___。
A. U0=0.45U2
B. U0=1.2U2
C. U0=0.9U2
D. U0=1.4U2
【单选题】
22温度影响了放大电路中的___,从而使静态工作点不稳定。
A. 电阻;
B. 电容;
C. 三极管;
D. 电源。
【单选题】
23用直流电压表测得放大电路中某三极管各极电位分别是2V、6V、2.7V,则三个电极分别是___。
A. [B、C、E]
B. [C、B、E]
C. [E、C、B]
【单选题】
24共射极放大电路的交流输出波形上半周失真时为___
A. 饱和失真
B. 截止失真
C. 交越失真
【单选题】
25三极管的反向电流ICBO是由___组成的。
A. 多数载流子
B. 少数载流子
C. 多数载流子和少数载流子
【单选题】
27如果在NPN型三极管放大电路中测得发射结为正向偏置,集电结也为正向偏置,则此管的工作状态为___
A. 放大状态;
B. 截止状态;
C. 饱和状态;
D. 不能确定。
【单选题】
28在以下三种电路中输入电阻最大的电路是___。
A. 共基放大电路
B. 共集放大电路
C. 共射放大电路
推荐试题
【填空题】
take a toll on,in other words ,drop out,in turn ,at risk (of) ,interfere with,be accustomed to, contribute to,cut back on ,hold on to When you move to a new country, you may find the food there strange and you may miss the familiar smells of the food [ ] in your country
【填空题】
take a toll on,in other words ,drop out,in turn ,at risk (of) ,interfere with,be accustomed to, contribute to,cut back on ,hold on to Although he kept trying and failing, I always [ ] the belief that he would succeed one day.
【填空题】
take a toll on,in other words ,drop out,in turn ,at risk (of) ,interfere with,be accustomed to, contribute to,cut back on ,hold on to The tax only affects people with an annual income over $200,000-[ ], it will only attect the very rich.
【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.