【单选题】
37若要让Timer作为外部计数只用，应如何设置？___
A. Gate=0
B. Gate=1
C. C/=0
D. C/=1
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相关试题
【单选题】
39下列哪个不是8×51所提供的省电方式？___
A. PD方式
B. IDL方式
C. LP方式
D. 待机方式
【单选题】
89S51的看门狗有何作用？___
A. 重复执行程序
B. 找回遗失数据
C. 复位系统
D. 防止中毒
【单选题】
41若要启用WDT，则应依次填入WDTRST寄存器哪些数据？___
A. 0xe1、0xe2
B. 0xe1、0x1e
C. 0x1e、0xe1
D. 0x10、0x01
【单选题】
8×51的定时器，在下列哪种方式下具有自动加载功能？___
A. Mode0
B. Mode1
C. Mode2
D. Mode3
【单选题】
45下列哪种AD转换器的转换速度比较快？___
A. 双斜率型AD转换器
B. 比较型AD转换器
C. 连续计数式AD转换器
D. 逐渐接近式AD转换器
【单选题】
46下列哪种AD转换器的精密度比较高？___
A. 双斜率型AD转换器
B. 比较型AD转换器
C. 连续计数式AD转换器
D. 逐步逼近式AD转换器
【单选题】
47对于8×8 LED点阵而言，其中的LED个数及引脚各为多少？___
A. 64、16
B. 16、16
C. 64、12
D. 32、12
【单选题】
48在共阳极型8×8 LED点阵里，其阳极如何连接？___
A. 各行阳极连接到行引脚
B. 各列阳极连接到列引脚
C. 各行阳极连接到列引脚
D. 各列阳极连接到行引脚
【单选题】
49在共阳极型8×8 LED点阵里，其阴极如何连接？___
A. 各行阴极连接到行引脚
B. 各列阴极连接到列引脚
C. 各行阴极连接到列引脚
D. 各列阴极连接到行引脚
【单选题】
50双色8×8 LED点阵的列引脚与行引脚各位多少？___
A. 12、12
B. 8、16
C. 16、8
D. 24、8
【单选题】
___的方向规定由高电位点指向低电位点。
【单选题】
三相电动势到达最大的顺序是不同的，这种达到最大值的先后次序，称三相电源的相序，相序为U-V-W-U，称为___。
【单选题】
电路的作用是实现能量的传输和转换、信号的___和处理。
【单选题】
电阻器反映导体对电流起阻碍作用的大小，简称___。
A. 电动势
B. 功率
C. 电阻率
D. 电阻
【单选题】
___反映了在不含电源的一段电路中，电流与这段电路两端的电压及电阻的关系。
A. 欧姆定律
B. 楞次定律
C. 部分电路欧姆定律
D. 全欧姆定律
【单选题】
并联电路中的总电流等于各电阻中的___。
A. 倒数之和
B. 相等
C. 电流之和
D. 分配的电流与各电阻值成正比
【单选题】
串联电路中流过每个电阻的电流都___。
A. 电流之和
B. 相等
C. 等于各电阻流过的电流之和
D. 分配的电流与各电阻值成正比
【单选题】
___的一端连在电路中的一点，另一端也同时连在另一点，使每个电阻两端都承受相同的电压，这种联结方式叫电阻的并联。
A. 两个相同电阻
B. 一大一小电阻
C. 几个相同大小的电阻
D. 几个电阻
【单选题】
___的电阻首尾依次相连，中间无分支的联结方式叫电阻的串联。
A. 两个或两个以上
B. 两个
C. 两个以上
D. 一个或一个以上
【单选题】
电流流过负载时，负载将电能转换成___。
A. 机械能
B. 热能
C. 光能
D. 其他形式的能
【单选题】
电功的数学表达式不正确的是___。
A. W=Ut/R2t
B. W=UIt
C. W=U2t/Rt
D. W=I2Rt
【单选题】
测量电压时，电压表应与被测电路___。
【单选题】
测量电流时,万用表的接线方法与直流电流表一样，应把万用表___在电路中。测量直流电压时，应把万用表与被测电路并联。
【单选题】
串联电路中各电阻两端电压的关系是___。
A. 各电阻两端电压相等
B. 阻值越小两端电压越高
C. 阻值越大两端电压越高
【单选题】
确定正弦量的三要素为 ___。
A. 相位、初相位、相位差
B. 最大值、频率、初相角
C. 周期、频率、角频率
【单选题】
当电压为5V时,导体的电阻值为5欧,那么当电阻两端电压为2V时,电阻值为___欧。
【单选题】
对称负载接成星形时,三相总电流___。
A. 等于零
B. 等于其中一相电流的三倍
C. 等于其中一相电流。
【单选题】
一段有源支路如图1所示，AB两端的电压UAB为___。
A. 10 V
B. —2V
C. 2V
D. —10V
【单选题】
如图2电路中，等效电阻=___
A. 150Ω
B. 900Ω
C. 600Ω
D. 100Ω
【单选题】
电流表的读数是4A，则电路中电流表的读数是 ___
【单选题】
在R、L、C串联电路中，已知＝3Ω，＝5Ω，＝8Ω，则电路的性质为 ___。
A. 感性
B. 容性
C. 阻性
D. 不能确定
【单选题】
工业生产中大量的设备均为感性负载，功率因数往往很低，常采取___的方法来提高电网的功率因数。
A. 并联电容
B. 串联电容
C. 串联电感
D. 并联电感
【单选题】
交流电压表及电流表指示的数值是___
A. 平均值
B. 有效值
C. 最大值
D. 瞬时值
【单选题】
RLC串联电路发生谐振，，R=10Ω，Ω，则谐振时的感抗为___
A. 10Ω
B. 40Ω
C. 20Ω
D. 30Ω
【单选题】
RL从电路获得最大功率，此时RL=___。
【单选题】
使用电解电容时___。
A. 负极接高电位，正极接低电位
B. 正极接高电位，负极接低电位
C. 正极接高电位，负极也可以接高电位
D. 不分正负极
【单选题】
开关接1时，电压表的读数为___。
A. 0V
B. 0.2V
C. 1.96V
D. 2V
【单选题】
开关接2时，电流表的电流为___。
A. 0A
B. 10A
C. 0.2A
D. 约等于0.2A
推荐试题
【单选题】
Q1:What is conversation mainly about?___
A. The woman's happy college life the man's doubt .
B. The woman's spending habits and the man's concerns .
C. The man's reminding the woman of the exam this Thursday .
D. The man's support for the woman over the past 15 years .
【单选题】
Q2:What did the woman do last night?___
A. She bought a new leather coat .
B. She studied very hard for an exam .
C. She treated all her friends to dinner .
D. She went to a concert with her friends .
【单选题】
Q3:Where did the woman get the money?___
A. She just received her student loan .
B. She saved some money for herself .
C. She borrowed the money from her friends .
D. She asked her mom to send her the money .
【单选题】
Q4:What is the man?___
A. A teacher of biology .
B. An undergraduate student .
C. A freshman in biology class .
D. A graduate teaching assistant .
【单选题】
Q1: What is this passage mainly about?___
A. How businesses can compete with each other .
B. How small businesses operate during holidays .
C. How small businesses manage holiday workers .
D. How can earn more money during holidays .
【单选题】
Q2: According to Rubin, what can small companies do to thank holiday workers?___
A. Have talks with their families .
B. Give them good extra benefits .
C. Offer them expensive holiday tokens .
D. Show appreciation to them face to face .
【单选题】
Q3: What can small business owners do to help holiday workers get into the holiday spirit?___
A. Entertain them with big meals .
B. Let them enjoy some holiday games .
C. Give them handmade thank-you cards .
D. Send their families some holiday gift cards .
【单选题】
Q4: Who are supposed to benefit most from this passage?___
A. Workers who have to work during holidays .
B. Employees who intend to earn extra money .
C. Big companies that usually close on holidays .
D. Small businesses that try to be more competitive .
【单选题】
In the first two paragraphs of the passage the writer tries to tell us that___
A. he had lived in Washington D.C. for twenty years
B. he was very imaginative when he was a child
C. he had fond memories of his old neighborhood
D. )he had come from a very poor neighborhood
【单选题】
The writer ,as a child ,was very fond of playing in the basement because ___
A. it was bright and alive
B. it contained a movie house and a space station
C. it was ideal for playing hide-and-seek
D. it was surrounded by trees and flowers
【单选题】
How did the writer feel when he visited his old neighborhood in Washington D.C. ?___
A. Greatly surprised .
B. Very regretful .
C. Quite excited .
D. Very sad .
【单选题】
On his visit to his hometown ,the writer found the old apartment building___
A. see medunfit to live in
B. had been repaired
C. could hardly be recognized
D. looked dirty and smelt horrible
【单选题】
" Youcan never go home again "inthe last sentence of this passage means that___
A. one should never revisit his hometown after many years of absence
B. one will never find his hometown the same as it was in his childhood memory
C. avisit to one's hometown will bring back one's fond memories of home
D. avisit to one's hometown will bring back many sad memorie
【单选题】
We learn from the passage that Tracy died___
A. on December 8,1992
B. of brain damage
C. 24 hours after he fell off the roof of a car
D. in a car crash
【单选题】
Tracy's parents decided to donate Tracy's organs because___
A. Tracy told them to do so just before he died
B. they wanted to save others the pain of seeing a dear one die
C. David's life could continue in a meaningful way
D. they knew David was suffering from a hopeless liver disease
【单选题】
The meeting between the writer's family and Tracy's parents was arranged because___
A. the writer and her husband wished to express their thanks to Tracy's parents
B. the local organ bank wanted to see how both families felt about the donation
C. Tracy's parents wanted to see someone whose life had been saved by the donation
D. the two families were linked by the most bittersweet ties imaginable
【单选题】
The writer and her husband learned how Tracy died___
A. from his parents
B. from the organ bank
C. from the hospital
D. from the doctor who performed the operation
【单选题】
The meeting between the two families helped to ease the Marshes'suffering because___
A. they saw that David looked very much like their son
B. they saw that David had regained health with Tracy's liver
C. they now had someone to share their memories of Tracy
D. they now knew for sure they had done the right thing
【单选题】
The writer's first marriage was unsuccessful because___
A. her husband often woke her up at midnight
B. her husband kept criticizing her
C. she was so unattractive
D. she had a self-esteem problem
【单选题】
When the writer asked for a divorce ,her husband___
A. told her that she would never find one who loved her as he did
B. delayed two years before giving her a reply
C. accused her of having an affair
D. said that she was unattractive and not worth loving
【单选题】
When the writer first met Clint ,she felt that___
A. she should have listened to her friend and met Clint earlier
B. Clint was a nice ,dazzling young man
C. Clint could not be really interested in her
D. she would find true love in Clint
【单选题】
The writer was particularly touched by Clint because___
A. he loved her children and asked for their approval of the marriage
B. he said that he could not imagine a life without her and the children
C. he believed that at 2 and 4 ,the two children were the "menof the house "
D. hekept her company and talked with her until the next morning
【单选题】
The writer's marriage to Clint is important to her mainly because___
A. it gave her and her sons a second chance to live a happy life
B. every day Clint would tell the writer that he loved her
C. it helped her to regain her self respect
D. it made her children happy ,which is all she cared about in life
【单选题】
What was Goodall's childhood dream ?___
A. She dreamed of going to college .
B. She dreamed of studying animals in Africa .
C. She dreamed of becoming a scientist .
D. She dreamed of traveling all around the world .
【单选题】
What did Goodall's mother think of her dream ?___
A. As a girl she should not go to the African jungle .
B. Her dream would remain a dream unless she got the right training .
C. As a girl she should stay away from violent animals .
D. She could make her dream come true if she was determined .
【单选题】
Goodall's most important discovery was that___
A. some animals use tools
B. like humans animals have emotions
C. chimpanzees could attack each other violently
D. termites are chimpanzees'favorite food
【单选题】
Goodall's success is chiefly due to her___
A. exceptional talents
B. scientific training
C. determination and patience
D. enthusiasm and good luck
【单选题】
What is Goodall doing now ?___
A. Studying animal behavior at Cambridge University .
B. Raising funds for the preservation of wildlife .
C. Observing chimpanzees in African jungles .
D. Working hard supervising postgraduate students.
【单选题】
___是我们理解当前所处历史方位的关键词。
A. 新时期
B. 新时代
C. 重要战略机遇期
D. 关键期
【单选题】
中国特色社会主义进入新时代,意味着科学社会主义在21世纪的中国焕发出强大生机活力,在世界上高高举起了___伟大旗帜。
A. 小康社会
B. 社会主义现代化强国
C. 和谐社会
D. 中国特色社会主义
【单选题】
“思想道德修养与法律基础”,是一门融思想性、政治性、科学性、理论性、实践性于一体的___课。
A. 专业基础
B. 通识教育
C. 思想政治理论
D. 专业选修
【单选题】
党的十九大提出到本世纪中叶,要把我国建设成富强、民主、文明、和谐、___的社会主义现代化强国。
【单选题】
思想道德和___都是调节人们思想行为、协调人际关系、维护社会秩序的重要手段。
【单选题】
中国特色社会主义思想道德建设和___紧密联系、相互促进,为中国特色社会主义事业提供坚实的思想基础、精神支撑和法治保障。
A. 中国特色社会主义文化建设
B. 中国特色社会主义经济建设
C. 中国特色社会主义政治建设
D. 中国特色社会主义法治建设
【单选题】
___是中国最早的现代大学。
A. 清华大学
B. 北京大学
C. 复旦大学
D. 浙江大学
【单选题】
《礼记·中庸》认为，道德修养应“莫见乎隐，莫显乎微，故君子慎其独也”。这种“慎独”的道德修养方法要求我们在学习“思想道德修养与法律基础”课时要注重___。
A. 学习科学理论
B. 理论联系实际
C. 知行统一
D. 多思考深理解
【单选题】
“业精于勤，荒于嬉；行成于思，毁于随”，这句话说明了学习必须做到___
【单选题】
大学生活的中心内容应是___
A. 社会活动
B. 培养动手能力
C. 恋爱
D. 学习
【单选题】
创新学习的基础是___
A. 实事求是
B. 解放思想
C. 求真务实
D. 善于思考
【单选题】
“知之为知之，不知为不知，是知也。”这句话告诉我们，在学习上一定要培养___的优良学风。
A. 求实
B. 一丝不苟
C. 勤奋
D. 敢为人先
