【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
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相关试题
【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
【单选题】
开关接1时，电流表中流过的短路电流为___。
A. 0A
B. 0.2A
C. 10A
D. 约等于0.2A
【单选题】
正弦交流电常用的表达方法有___。
A. 解析式表示法
B. 波形图表示法
C. 相量表示法
D. 以上都是
【单选题】
电感两端的电压相位超前电流___。
A. 90°
B. 180°
C. 360°
D. 30°
【单选题】
电容两端的电压相位滞后电流___。
A. 30°
B. 90°
C. 180°
D. 360°
【单选题】
应用戴维南定理求含源二端网络的输入等效电阻是将网络内各电动势___
【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
【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
推荐试题
【单选题】
What does the speaker do? ___
A. Public relations consultant.
B. Home cook.
C. Website administrator.
D. Writer.
【单选题】
Which is NOT included in the speaker’s favorite breakfasts? ___
A. Egg.
B. Prosciutto.
C. Papaya.
D. Cabbage.
【单选题】
When do the students start learning Chinese? ___
A. Since kindergarten
B. Since elementary school
C. Since middle school
D. Since high school
【单选题】
When can the students continue studying Chinese? ___
A. In elementary school and middle school.
B. In middle school and high school.
C. In high school and university
D. After the university.
【单选题】
How many American students are currently learning Chinese? ___
A. About 22,000
B. About 24,000
C. About 44,000
D. About 2,400
【单选题】
How much did the Defense Department give Oregon schools? ___
A. $70,000
B. $1.3 million
C. $700,000
D. $1.3 billion
【单选题】
What’s Isabel Weiss’s purpose of learning Chinese? ___
A. For fun
B. For more opportunities for jobs
C. For more opportunities of making money
D. For more opportunities for promotions
【单选题】
What ability do the standardized tests reward to? ___
A. Think.
B. Create.
C. Quickly answer superficial questions.
D. Above all.
【单选题】
In what ways the IQ scores can be changed? ___
A. Training.
B. Nutrition.
C. More friendly people administered the test.
D. Above all
【单选题】
What do schools focus on? ___
A. Concepts.
B. Science.
C. Social Studies.
D. Foreign languages.
【单选题】
Why tests and standards are a necessary fact of life? ___
A. They protect us from hazardous products.
B. They protect us from inept drivers.
C. They protect us from shoddy professionals.
D. Above all.
【单选题】
How many percent did the scores on statewide tests rise? ___
A. 4%.
B. 14%.
C. 40%.
D. None.
【单选题】
What was the woman’s reaction when she was nominated? ___
A. She was surprised at the nomination.
B. She was calm at the nomination.
C. She was indifferent to the nomination.
D. She was scared of the nomination.
【单选题】
According to the woman, who paid for her trip to San Francisco? ___
A. Her trip to San Francisco was sponsored by the Academy.
B. Her trip to San Francisco was paid for by her company.
C. Her trip to San Francisco was paid for by her family.
D. Her trip to San Francisco was paid for by herself.
【单选题】
What is the name of George Miller’s new movie? ___
A. Happy Feeling.
B. Happy Dancing.
C. Happy Foot.
D. Happy Feet.
【单选题】
Which name is not mentioned in the film? ___
A. Nicole Kidman.
B. Hugh Jackman.
C. George Clooney.
D. Robin Williams.
【单选题】
Which of the following statement is not true about “Life in the Freezer”? ___
A. It was a documentary film.
B. It was made by National Geographic and the BBC.
C. It was a story of the amazing life of Emperor penguins.
D. The
E. mperor penguin sang to each other to find a mate and made friends.
【单选题】
What should you do during a high-pressure periods? ___
A. Lock yourself in a room with your work.
B. Leave your work and go on a vocation.
C. Tell your boss you can’t finish your work.
D. Get together with people who will revitalize and inspire you.
【单选题】
Which of the following is the correct description of TempWorld? ___
A. The era of guaranteed jobs is history.
B. We are all temporary workers.
C. You have to equip yourself with the skills.
D. All of the above.
【单选题】
What should a career activist do? ___
A. Being a career activist means concentrating on daily business.
B. Being a career activist means you can do a business as long as it meets your short-term needs.
C. A career activist should take the long view of his career.
D. A career activist should plan everything in advance.
【单选题】
What should you do in the TempWorld? ___
A. In TempWorld you must withstand disappointment, juggle stressful situations, and handle pressure.
B. You must learn from your setbacks and use them to your advantage in the future.
C. Things always go well for successful people because they are honest.
D. Both A and B.
【单选题】
Which of the following statements is Not True? ___
A. Your boss may be willing to change his behavior than your think.
B. Some managers don’t care how much their words or actions upset staffers.
C. You should tell your managers how their outbursts make you feel.
D. If the boss values your work, he may stop his abusiveness.
【单选题】
Which of the following public places is NOT mentioned that have banned mobiles? ___
A. restaurants
B. gas stations
C. theatres
D. museums
【单选题】
What happened when the cellphone of the speaker’s friend rang? ___
A. His friend answered the phone and the speaker became invisible to his friend.
B. They answered the phone together.
C. The speaker threw away his friend’s cellphone.
D. His friend hung up the phone and kept talking to the speaker. (C)
【单选题】
What happened to the man? ___
A. He had a car accident.
B. He had his arms broken.
C. He lost his mobile phone.
D. He was not able to use his mobile because he was in a remote area.
【单选题】
Which of the following is NOT true? ___
A. Today there are about 400 million cellphone owners.
B. Today there are about 300 million Personal Computer subscribers.
C. Cellphones will be more often used.
D. Cellphones will completely replace Personal Computers.
【单选题】
Which of the following is true? ___
A. Ellen Johnson-Sirleaf stayed in her country during the nation’s civil war.
B. She is still working for the United Nations.
C. She is the first woman ever elected president of an Asian country.
D. She is a Liberia.
【单选题】
What do you know about the solar eclipse? ___
A. Only hundreds of people gazed at it.
B. It was caused by the earth passing in front of the moon.
C. It was not often seen.
D. It started in Mongolia and ended in Brazil.
【单选题】
What is true about this meeting between the USA and China? ___
A. It was a meeting between Xi Jinping and Donald Trump.
B. It was the first time that the Chinese president had visited the United States.
C. The issue of the Olympics was discussed.
D. South Korea’s nuclear weapons program was discussed.
【单选题】
In which year did the station’s first permanent crew arrived? ___
A. 1998
B. 2000
C. 2002
D. 2003
【单选题】
If elected, ________________. ___
A. Richardson would be the first Hispanic President.
B. Clinton would be the first African-American President.
C. Romney world be the first Hispanic President.
D. Clinton would be the first Mormon President.
【单选题】
What are the things that the speaker’s inner and outer life based on? ___
A. Money
B. Health
C.
D. elicious food
【单选题】
What kind of things has its own reason for existing? ___
A. Questioning
B. The structure of reality
C. Curiosity
D. The mysteries of eternity
【单选题】
Who are so full of doubts? ___
A. Fools and fanatics
B. Wise people
C. Professors
D. University students
【单选题】
To the speaker, what kind of things always win in life? ___
A. Truth and love
B. Power and status
C. Great minds
D. Money and material
【单选题】
What’s the key word of the speaker? ___
A. Love
B. Power
C. Freedom
D. Curiosity
【单选题】
What happened to the man? ___
A. He committed identity theft.
B. He was put in prison.
C. He reported a case of theft to police.
D. He robbed a bank.
【单选题】
What is the attitude of Mrs. Washington? ___
A. She tries to cover up for little George.
B. She thinks Mr. Washington should not ask George directly.
C. She encourages George to chop down the tree.
D. She thinks Mr. Washington should put the blame on the sharp axe.
【单选题】
What do Nancy’s colleagues think about her transgender transition? ___
A. They think it is ridiculous.
B. They make a big fuss about it.
C. They take it lightly.
D. They are sympathetic.
【单选题】
What are the two women talking about? ___
A. They are talking women’s liberation.
B. They are talking about an ideal husband.
C. They want a rewarding job.
D. They are talking about women’s choice between family and career.
