相关试题
【单选题】
29在Keil µVision3里进行调试/仿真时，在哪里操作才能触动程序中断？___
A. 在Interrupt System
B. 在Cotorl Box对话框里
C. 直接单击魔术棒按钮即可
D. 直接按0键
【单选题】
30在8×51所提供的中断功能里，下列哪个优先级比较高？___
A. T1
B. RI/TI
C. T0
D. INT0
【单选题】
31在TCON缓存里，IE1的功能是什么？___
A. 触发 IE1中断
B. 指示IE1中断的标志
C. 提高IE1优先等级
D. 取消IE1中断
【单选题】
32在Keil C里，中断子程序与函数又何不同？___
A. 中断子程序不必声明
B. 函数不必声明
C. 中断子程序必须有形式参数
D. 中断子程序一定会有返回值
【单选题】
33若要同时启用INT0及INT1中断功能，则应如何设置？___
A. TCON=0×81
B. IE=0×85
C. IP=0×83
D. IE=0×03
【单选题】
35在8×51的Timer里，若使用Mode 0，其最大计数值为多少个机器周期？___
A. 65636
B. 8192
C. 1024
D. 256
【单选题】
36在12MHz的8×51系统里，哪一种方式一次可定时5ms？___
A. Mode 0及Mode 1
B. Mode 1及Mode 2
C. Mode 2及Mode 3
D. Mode3及Mode 1
【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
【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 ___
推荐试题
【单选题】
- How is it that you are late for class again?___
A. Because I missed the bus
B. By bus and then on foot
C. Yes, it is quite wrong
D. It is far from school
【单选题】
- Excuse me. Could you spare me a few minutes? - ___
A. Of course.
B. Of course not.
C. I am sorry to hear that.D.Yes. I'm busy now.
【单选题】
- It's very thoughtful of you to give me a ride. ___
A. It's my pleasure.
B. Take it easy.
C. Sure.
D. Never mind.
【单选题】
- This is heavy! What's in it? ___
A. I think you don't like it.
B. My new computer. I just bought it.
C. I'm glad you're here.
D. Are you really interested in it?
【单选题】
___ I'd like to place an order please.
A. Can I help you?
B. I can help you.
C. What are you doing?
D. Why are you doing?
【单选题】
- Do you know the girl over there?___
A. How can I know?
B. Yes, I remember it now.
C. It's Sam, my teacher's daughter.
D. She is a good girl.
【单选题】
- Shall we go out for dinner tonight?____
A. No, you can't.
B. Yes, please.
C. Thank you, I don't want to.
D. Sorry, I have a report to finish.
【单选题】
- I think the reference book（参考书）is very helpful.____
A. Good idea.
B. So do I.
C. With pleasure.
D. No problem.
【单选题】
- I wish you success in your career.____
A. You are welcome.
B. I think so.
C. Yes, please.
D. The same to you.
【单选题】
- Would you like to come over tonight?____
A. Yes, last night.
B. Yes, over there.
C. Sure, I'd love to.
D. Yeah, I liked it too.
【单选题】
- How do I transfer calls? ____
A. Do as you like.
B. It is a bit difficult.
C. Let me show you.
D. Not at all.
【单选题】
- Thanks for inviting me, John, but I've already made other plans. ____. Maybe another time.
A. I hope you enjoy it
B. That's good
C. Oh! I'm sorry to hear that
D. Great! I really had a good time
【单选题】
- Thanks for the lovely party and the delicious food. ____
A. No, thanks.
B. Never mind.
C. Thank you for coming.D.That's all right.
【单选题】
- Why didn't you tell me? ____
A. Sorry, I forgot.
B. I'm sorry you should wait.
C. I don't know.
D. I'd love to.
【单选题】
- What do you plan to do after the exam? ____ How about you?
A. I hate taking exams.
B. I like making plans.
C. Nothing special.
D. I've changed my mind.
【单选题】
- Tom told me that you collect stamps. ____
A. What do you mean?
B. I don't think so.
C. Why did he tell you?
D. Yes, I do. Do you?
【单选题】
- This is a challenging job. Who wants it？____
A. I'll take it.
B. It's a good idea.
C. You bet!
D. No sweat!
【单选题】
- I'm taking my driving test tomorrow. ___!
A. Cheers
B. Good luck
C. Come on
D. Congratulations
【单选题】
- ABC Company, may I help you? ____
A. I am Jack. May I speak to Miss Jenny?
B. This is Jack speaking. May I speak to Miss Jenny?
C. This is Jack speaking. Can I find Miss Jenny?
D. I am Jack. Can I find Miss Jenny?
【单选题】
- You have won the football game. Congratulations! ____
A. We are really lucky.
B. No one else could do it.
C. Oh, not really.
D. It's nice of you to say so.
【单选题】
- Excuse me, when will the 17:15 train arrive____
A. I don't tell you.
B. It's been delayed one hour.
C. You have to be patient.
D. Don't ask me.
【单选题】
- Is John there?____
A. Speaking.
B. I'm not Mary.
C. Who are you?
D. Mary is well today.
【单选题】
- Would you like to join us for Sunday dinner____
A. It's nice of you to invite me.
B. How about the food?
C. I like onion soup.
D. I'm sorry I missed the fun last time.
【单选题】
- Could you tell me where the nearest parking lot is?____
A. Don't ask me.
B. Parking is very difficult.
C. Sorry, I'm a stranger here.
D. Sorry, you can't park here.
【单选题】
- Sorry, ___
A. here you are.
B. take it.
C. it's taken.
D. never mind.
【单选题】
－What's this in English? ____
A. It's a map.
B. That is a map.
C. Yes, it's a map.
D. No, it isn't.
【单选题】
- I hear you got through your exam. Congratulations!____
A. No. I didn't do well enough.
B. Who told you that?
C. Thanks.
D. Yes, I got a good mark.
【单选题】
- Don't forget to come to my party this evening!___
A. I can't.
B. I won't.
C. I don't.
D. I will.
【单选题】
- Jim, please don't put your head out of the window on the bus. It's dangerous!___
A. Good idea.
B. Sorry, I won't do it again.
C. It doesn't matter.
D. It's good.
【单选题】
-How about going fishing?___, I have no patience for that.
A. Excuse me
B. Sorry
C. Pardon
D. Apologize
【单选题】
- Thanks for the lovely and delicious food______.
A. No thanks
B. Never mind
C. All right
D. My pleasure
【单选题】
－ Haven't seen you for ages. Let's have a get-together next week._____
A. Great idea.
B. Welcome!
C. Yes, of course.
D. No, thanks.
【单选题】
- Do you mind if I switch off the radio? ______. Go ahead.
A. Never mind
B. No way
C. No, not at all
D. No, you'd better not
【单选题】
- Could I use your bike for a moment? ___
A. It's well.
B. It doesn't matter.
C. By all means.
D. I have no idea.
【单选题】
-How do you like the story?_______.
A. I'd like to read it
B. I like it very much
C. fine, thank you
D. It's very interesting
【单选题】
- I'll sorry to trouble you.______.
A. Don't say so
B. OK
C. It doesn't matter
D. That's fight
【单选题】
- We ordered 20 boxes of your products, but we have only got 19. - ____
A. You do not have to.
B. It does not matter.
C. We will send another tomorrow.
D. Nothing serious.
【单选题】
--Will you please give the note to him? _________.
A. Certainly, I'll give it to him
B. No, please not
C. Sorry, I don't
D. Yes, please do
【单选题】
- Thank you ever so much for your lovely gift____
A. Never mind
B. I'm glad you like it.
C. Please don't say so.
D. No, It's not so good.
【单选题】
- I'd like to invite you to dinner this Saturday, Mr. Smith.____
A. Oh, no. let's not.
B. I'd rather stay at home.
C. I'm sorry, but I have other plans.
D. Oh, no. That'll be too much trouble.
