电专科电工电子技术期末复资料考试抄
简答题
1恒压源性质什？
答：（1）输出电压始终恒定受输出电流影响（2）通电流身决定相连负载电阻决定
2恒流源性质什？
答：恒流源性质（1）输出电流始终恒定受输出电压影响（2）恒流源端电压身决定相连负载电阻决定
3负载增加涵义什？似恒压源供电似恒流源供电系统中负载增加相负载电阻增减？
答：负载增加意指电路输出功率增加似恒压源供电系统中负载获功率PUI负载增加负载电流增相负载电阻减
似恒流源供电系统中负载获功率PUII2R负载增加负载电压增相负载电阻加
4电压源模型电流源模型等效变换条件什？
答：果电压源模型输出电压输出电流电流源模型输出电压输出电流应相等说外部电路言二者伏安特性相两种模型等效互换
5基尔霍夫定律基容什？适范围？
答：KCL定律：意时刻流入电路中节点电流恒等流出该节点电流0
KVL定律：意时刻电路中闭合回路绕行周段电压代数恒零0
6作线性电路分析中重定理简述叠加定理基容适范围？
答：包含电源线性电路电路某元件电流电压等电源单独作该元件产生电流电压代数叠加定理分析计算线性电路中电流电压计算功率
7电路分析计算中戴维南定理适宜应种情况？
答：果需计算电路中某支路电流时适宜采戴维南定理
8三素？行正弦交流电量瞬时波形图标出3素
答：幅值频率初相
9简述RLC串联电路产生串联谐振特点？
答：（1）电路阻抗呈电阻性 （2）电路中电流
（3）XLXC串联谐振电容电感两端产生高电压
10简述提高功率数意义？
答：电源够传送少功功率负载功率数cos直接关系cos1说明输出功率全部功功率电源设备充分利cos 说明电源设备容量利程度低功率数造成电源设备浪费
11三相交流电路中负载星形连接时相电流线电流相电压线电压关系？
答相电流线电流关系IPIL 相电压线电压关系ULUP
12三相交流电路中称负载三角形连接时相电流线电流相电压线电压关系？
答：相电流线电流关系ILIP 相电压线电压关系UPUL
13异步电动机起动求什？说明原
答：（1）足够起动转矩电动机克服负载转矩迅速旋转起 （2）起动电流太否会供电电网产生较电压降影响电网电气设备正常工作
14三相异步电动机调速方式种？
答：三种：（1）改变电源频率调速（2）改变转差率调速（3）异步电动机变极调速
15三相异步电动机控制方式种？
答：直接起动控制（点动长动）正反转控制时间控制行程控制
16果需电动机连续运行三相异步电动机功率选择注意什？
答：功率选择应该产生机械需实际功率选择效率功率数会低济选择电动机长时间工作外额定载状态仅保证正常工作造成电动机损坏
17三相鼠笼式异步电动机相较绕线式异步电动机优点什？
答：绕线式异步电动机优点转子回路中接入附加电阻改善电动机起动性起动转矩增起动电流减者调节异步电动机转速
18表示三相异步电动机起动力？三相异步电动机正常工作时电源电压允许波动范围少？
答：般异步电动机起动转矩额定转矩值Tqd TN 表示电动机起动力通常情况异步电动机起动力取值Tqd TN11~22间三相异步电动机正常工作时电源电压允许波动范围应该正常电压
19什控制电器？什低压电器？低压电器分两类？
答：谓控制电器指电路中起通断保护控制调节电器件控制电器中额定电压500V称低压控制电器低压控制电器分两类手动控制电器动控制电器
20接触器分两类？接触器功什？方？
答：接触器种动电器直流接触器交流接触器分功频繁接通断开交直流电路容量控制电路控制电动机电热设备电焊机等尤电力拖动系统中应广泛
21什正偏置反偏置？二极正偏置反偏置时分什状态？
答：PN结P区接电源正极N区接电源负极时称外加正电压正偏置P区接电源负极N区接电源正极时称外加反电压反偏置
正偏置时二极处导通状态反偏置时二极处截止状态
22稳压二极起稳压作？
答：稳压二极相普通二极较低反击穿电压特性曲线反击穿特性曲线陡击穿安全工作电流范围够保证电压变化串接限流电阻够稳压二极稳定工作指定反击穿区输出电压取稳压二极两端输入电压稳定情况稳压二极便起稳定输出电压作
23什说三极电流控制器件？
答：量控制角度基极电流控制信号变化够直流电源提供三极较量起控制作表现发射极集电极电流变化进行控制
24基放电路组成原什？
答：1．电路中直流通路交流通路 2．电路线性元件非线性器件组成
3．三极工作放状态保证信号失真超允许范围
25放电路信号源电阻RS输入电阻Ri电压放倍数影响？
答：信号源阻输入电阻分压作影响放电路信号源电阻RS越高电路电压放倍数越输入电阻Ri越高电路电压放倍数越
26什三极放电路饱失真截止失真？避免？
答：输入交流信号较静态工作点设置高信号正半周器件进入饱区造成波形失真称饱失真反静态工作点设置低信号负半周器件进入截止区造成波形失真称截止失真两种失真器件非线性特性造成统称非线性失真
避免出现饱失真截止失真调节电阻RBRC电源UCC静态工作点负载线移动改变负载线斜率静态工作点移合适位置
27分析计算运放电路时常三项理想化指标什？
答：（1）开环差模电压放倍数Aod穷（2）差模输入电阻Rid穷（3）差模输出电阻Rod零
28引入负反馈放电路性改善益处？
答：起稳定静态工作点提高放倍数稳定性改变输入输出电阻减失真拓展通频带等
29引入电压串联负反馈电流联负反馈放电路输入输出电阻分什影响？
答：引入电压串联负反馈会输入电阻增输出电阻减引入电流联负反馈会输入电阻减输出电阻增
30直流稳压电源般部分组成？
答：变压器整流电路滤波电路稳压电路四部分组成
31逻辑代数中应反演律原函数变反函数需进行互换？
答：三种互换：运算（·）运算（+）互换逻辑常量10互换原变量反变量互换（偶规进行两种互换需原反变量互换）
32 门非门余输入端应处理？门非门余输入端应处理？CMOS电路余输入端否允许悬空？
答：门非门电路余输入端应接低电位门非门余输入端应接高电位（TTL电路输入端悬空相高电位）CMOS电路输入端允许悬空
33 组合逻辑电路逻辑功电路结构特点什？
答：组合逻辑电路特点：逻辑功：输出时输入逻辑值关该时刻前输入电路状态均关称没记忆功电路结构构成组合逻辑电路门电路间没反馈环路
34 组合逻辑电路分析步骤什？
答：逻辑图中门输出端加标注写出门输出逻辑函数表达式门输出逻辑函数表达式进行迭代进行必化简写出真值表说明该电路途
35 结合图1电路图简述执行置位功程
答：置位称置1程：
置位功：S0R1时置位端效低电位非门U1输出高电位实现置位功Q1时非门U2两输入R1Q1输出Q0满足两输出互补条件
图1
36 型JK触发器CP升作动作特点？
答：型触发器称电位触发型方式动作特点：时钟CP升前刻瞬间JK接收输入信号求CP1期间输入状态保持稳定时钟降产生输出
37 边型JK触发器CP脉信号作动作特点？（分负边正边两种情形）
答：负边型（降触发型）：CP降前刻瞬间JK接收输入CP降产生输出正边型（升触发型）：CP升前刻瞬间JK接收输入CP升产生输出
38写出JK触发器特性方程确定述种情形输出次态（Qn＋1）
说明触发器应功
J1时Qn0时
K1时Qn1时
J0K0时初态Qn时
J1K1时初态Qn时
答：JK触发器特性方程：
Qn＋1JQn +KQn
J1时Qn0Qn＋1实现置位功
K1时Qn1Qn＋1 0实现复位功
J0K0时Qn＋1Qn实现保持功
J1K1时Qn＋1Qn实现翻转功
39 射极输出器特点
答：输出电压输入电压基相(似1略1)相位相输入电阻输出电阻
三综合题
1．已知正弦交流电流t0时值i(o)A已知初相角600试求
效值t01秒时值i(01)2A试求电流周期频率(8分)
解：瞬时值表达式
1图11示电路测量电源数值阻图中标出UR0组成某实际电压源已知R126ΩR255Ω开关K1闭合K2开时电流表读数2A开K1闭合K2读数1A试求UR0
•
R2
R1
R0
º
º
图11
•
U
K2
K1
º
º
解：K1闭合K2开I1（R0+R1）U
K1开K2闭合 I2（R0+R2）U
联立两式出 U58V R003Ω
2图12示电路中已知U1 U2 U32VR1 R2 R33Ω求UABUBCUCA少？
图12
R2
R1
R3
+
U2
+ U1
U3
+
解：设流ACB回路电流I根基尔霍夫定律
（R1+R2+R3）IU3U2+U1 求出IA
UABU1IR1V UBCU2IR22V UCAUABUBCV
3戴维南定理求图13电路中R5支路电流已知R1R2R4R55Ω
B
R310ΩU65V
D
C
A
R5
R4
R3
R2
R1
+
U
图13
解：断开R5求开路电压UO入端电阻R0
UBD U≈433V UCD U325V UBC UBD+UDCUBDUCD108V
U短路 R0（R1R3）+（R2R4）≈583Ω
求出电流I5 I5≈01A
4已知某正弦电压t0时值 u0110V初相600求效值
解：正弦电压瞬时表达式 uUmcos（ωt+600）
t0时 u0 Umcos600
Um220V U220V
5电感线圈接电压40V直流电源时测线圈电流4A接电压220V频率50HZ正弦交流电源时测电流10A求线圈电阻电感
解：直流电源作时 XLωL0R40410Ω
交流电源作时 Z22Ω
XL196Ω
L624mH
6图4示电路中已知电压表读数15V电流表读数1AR5Ω电源角频率ω200rads求电感L电路消耗功率
解：设电流参考相量I 00 A电阻R电压相量R
5 00 V电感电压超前电流相位900
UL1414V
XL1414Ω L70Mh PI2R5W
7已知RLC串联电路R10ΩL2mHC180pF电源电压5V求谐振频率f0谐振电流I0品质数Q0
º
•
UR
R
º
•
图4
LR
谐振频率 f02654KHZ
谐振电流 I005A
XLω0L3333Ω XC3333Ω Q0333
8已知交流信号源阻250欧姆通变压调变压器接25欧姆负载RL变压器初级等效电阻等信号源阻时信号源输出功率负载获功率问变压器变压应该少？
解：根K2变压器初级等效电阻R＇L K2RL25K2
变压器初级等效电阻等信号源阻时信号源输出功率：
R＇L K2RL25K2250
K2100
变压K10时负载获功率
9台三相异步电动机磁极数p2工作额定电压380V额定频率50Hz已知额定转速1450rmin求步转速额定转差率？
解：1）步转速n11500rmin
2）额定转差率sN0033
10台三相异步电动机额定功率10KW额定电压380V额定转速980rmin额定工作效率η95额定工作电流IN18A起动力系数15载系数22
求：1）电动机功率数
2）起动转矩Tqd转矩Tmax
解：1）电动机额定输入功率Kw
定子三相绕组：
电动机功率数091
2）额定转矩975Nm
起动力系数15起动转矩：
14618Nm
载系数22转矩
2144Nm
R
11图2示电路输入端加幅值10V正弦波电压试画出输出端电压u0波形设稳压D1D2稳压值均6V
+
+
º
•
º
D1
D2
u0
ui
º
•
º
图2
解：
67
0
67
t
t
u0
10
0
12 图1（a）（b）示电路中计二极正压降U12电压值少？
（a） 图1 （b）
解：图(a)U123V图(b)U126V
13基射放电路图3示已知：UCC＝67VRb300kWRc2kW三极β100rbb 300WUBE07VC1C2容量足够试求：
（1）静态工作点IBQ＝？ICQ＝？UCEQ＝？ （2）电压放倍数Au
图3
解：IBQ002mAICQ＝2mAUCEQ＝27V
AuβRC rbe－100´2´10316´103＝－125
14判断图4（a）（b）示电路否失真放交流信号说明原
（a） (b)
图4
解：图3（a）（b）示电路均失真放交流信号中图（a）中缺少基极偏置图（b）中缺少发射极电阻
15图5分压式偏置放电路图中4处错误请指出
º
UCC
•
RB1
C2
C1
•
º
•
º
RL
RB2
C3
•
•
•
•
º
º
解：（1）C3应接三极发射极端（2）发射极端需接REC3联（3）三极集电极应接电阻RC（4）电源电压UCC应正电压
16说明图6示电路种运算电路已知：R112kWRF18kW输入电压uI05V时试求输出电压值uO
图6
解：该电路反例运算电路uO－075V
Ui1
17图7（a）示运放具理想特性设两输入电压波形图7（b）士示试画出电压u0波形
1
0
1
t
R
R
Ui2
Ui1
•
º
∞
t
1
0
1
U0
º
Ui2
R
•
•
º
+
+
R
（a） 图7 （b）
解： 图示电路标准减法器直接运公式求：
t
u0
1
0
1
u0（ui2 ui1） ui2 ui1
画出输出波形图示
18图8示两级运放电路已知R1RF110kWR2R3RF220kWuI11VuI205V计算电路输出电压uO说明该电路够实现种功
图8
解：u005V该电路减法运算电路
19 三位二进制数码高位低位分送电路三输入端求三
位数码中奇数1时电路输出1否0试画出逻辑图
解：（1）根提出逻辑功求列出真值表表
A
B
C
F
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
1
0
1
0
0
1
（2）根真值表列写出函数表达式
F
式中
F
B⊕A⊕C
画逻辑图
F
C
B
A
1
1
表达式画出逻辑图图示两异门构成
20 根图示波形利非门画出实现逻辑功逻辑图
A
t
B
t
C
t
F
t
解：解 采正逻辑高电逻辑1低电逻辑0根波形列出真值表表
A
B
C
F
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
1
1
1
0
0
0
21图组合逻辑电路进行分析写出逻辑函数FIF2F3表达式指出逻辑功
解 ：FlA
F2B
F3 A十B
逻辑功实现两位二进制数较功
22 8线－3线优先编码器74148逻辑框图功表图示分析逻辑功
0
逻辑图 功表
（1） 输入输出效电位什？
（2） L表示低电位H表示高电位x表示高电位者低电位输入01234567xxxxxxL时输出A2A1A0值？相什十进制数？
（3） 输出A2A1A0LLH110＝(6)10相十进制数6时输入01234567值？
解：（1）答：根功表知输入输出均低电位效电位
（2）答：01234567xxxxxxL0000001输出A2A1A0LLL111＝(7)10相
十进制数7
（3）答：A2A1A0LLH110＝(6)10相十进制数6时输入01234567xxxxxLH00000107脚效高电位反映出优先编码器功
23中规模计数器74161构成计数电路图示设计数器初态0QDQCQBQA0000（1）绘出计数状态图（2）分析计数长度少？
解：设计数器初态0QDQCQBQA0000绘出计数状态图 0000>0001>0010>0011>0100>0101>0110>0111>1000>1001>1010>1011>
计数器循环计数状态7计数长度7七进制加法计数器
24 图二进制加法计数器74161构成计数电路构成八进制计数电路（1）设计数器初态0QDQCQBQA0000绘出计数状态图（2）完成电路正确连接
解：设计数器初态0QDQCQBQA0000绘出计数状态图
000>0001>0010>0011>0100>0101>0110>0111>1000>1001>1010>1011>
正确电路图见图示
请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄The battle for young viewers CCTV is embracing Internet culture and working with independent producers on TV shows to woo audiences under 35 Han Bing bin reports After charming audiences with his warm smile for 14 years China Central Television host Li Jiaming recently found himself targeted by a group of young netizens unhappy with his style The complaints came after Li hosted the premiere of Rising Star on Oct 31 It is a singing competition show that originated in Israel Many young netizens found his hosting style slow and boring and mocked it as CCTV evening gala style They even initiated an online campaign to replace him The 40yearold host＇s reaction to the criticism was surprising During the second episode he jokingly called himself the slow Jiaming and acted much younger talking faster and louder It＇s like selling a product When the customers file a complaint you must change says Li In the Internet age you get feedback very quickly These young people are so cute When you＇re willing to change for them they will quickly like you back In order to win more young viewers CCTV is relying on programs such as Rising Star to embrace Internet culture In Rising Star a studio audience and fans watching on television vote for their favorite singers in real time using the instantmessaging app WeChat Rising Star was designed to be a live broadcast but the Chinese version isn＇t because of policy reasons Still WeChat votes by viewers at home are still a major factor in determining which contestants advance to the next round In the show＇s latest episode more than 65 million votes were cast via WeChat Now the competition among entertainment shows is very fierce Audiences have more diverse needs CCTV needs to embrace an open attitude interact with young audiences and blend with the Internet says Lyu Yitao director of CCTV＇s entertainment channel The producer of Rising Star Enlight Media says the program will have a phenomenal effect given CCTV＇s audience base nationwide But it comes with a challenge says Zhang Hang chief producer of the program and CEO of Enlight Media＇s TV business Unlike topranking provincial satellite channels such as Hunan TV which have a large base of young fans thanks to a series of phenomenally popular entertainment and reality shows CCTV productions are usually more conservative and serious and thus have a much older audience base If we were to run this program on Hunan we may attract twice as many viewers says Zhang But since we didn＇t make it there we now have to make the best out of the given conditions And it means we have to make certain compromises When the current season of Rising Star ends Zhang says his company will conduct an overall evaluation of the program and make adjustments for future seasons Although audience ratings haven＇t lived up to Zhang＇s expectations he says the program has already helped CCTV attract more young people According to Enlight Media the number of people ages 15 to 35 who watched the first episode of Rising Star was 76 percent higher than the usual audience for CCTV entertainment productions In order to attract young audiences CCTV has been working with independent production companies As one of CCTV＇s closest partners Enlight Media has produced several entertainment and reality shows for the company＇s channels including the Chinese version of The Biggest Loser on CCTV＇s business channel and an original teenager talent show Shaonian Zhongguo－qiang (Strong Young Chinese) on CCTV1 This year CCTV also licensed EEMedia the producer of the popular Super Girl talent shows to produce the talk show Hi 2014 hosted by Taiwan pop star Harlem Yu and one of China＇s most popular TV stars Xie Na The show is geared toward younger audiences Canxing Productions which rose to fame with the success of its Voice of China series on Zhejiang TV also produced two talent shows for CCTV One is an original production called Songs of China which ended up as one of CCTV＇s most watched programs of 2014 The State Administration of Press Publication Radio Film and Television announced earlier this year that starting in 2015 only one music talent show can be aired nationwide during prime time each season and there can be only one program based on foreign formats each year However domestic media report that such policies don＇t apply to CCTV meaning it will become a highly desired platform by production companies Wang Changtian CEO of Enlight Media confirmed to the Shanghai Securities News that its programs scheduled to air on CCTV next year which include at least two reality shows won＇t be affected A kung futhemed reality show produced by Canxing is also reportedly scheduled to run on CCTV next year CCTV is very active The level of its acceptance of new ideas is even beyond my imagination says Zhang Hang Our cooperation with CCTV will surely continue When winter comes nothing is more relaxing than a hot spring bath For thousands of years natural mineralrich hot spring baths have also been used to relieve health ailments The water found in natural hot springs contains a variety of different minerals and the most common one is sulfur It has a rotten egg smell but is excellent for skin The sulfurcontaining water might be just what the doctor ordered when it comes to relieving pain stress itchy skin arthritis and more Hot springs resorts are thriving as biting cold winter arrives Here we take a look at some of the best natural hot springs China has to offer
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简答题
1恒压源性质什？
答：（1）输出电压始终恒定受输出电流影响（2）通电流身决定相连负载电阻决定
2恒流源性质什？
答：恒流源性质（1）输出电流始终恒定受输出电压影响（2）恒流源端电压身决定相连负载电阻决定
3负载增加涵义什？似恒压源供电似恒流源供电系统中负载增加相负载电阻增减？
答：负载增加意指电路输出功率增加似恒压源供电系统中负载获功率PUI负载增加负载电流增相负载电阻减
似恒流源供电系统中负载获功率PUII2R负载增加负载电压增相负载电阻加
4电压源模型电流源模型等效变换条件什？
答：果电压源模型输出电压输出电流电流源模型输出电压输出电流应相等说外部电路言二者伏安特性相两种模型等效互换
5基尔霍夫定律基容什？适范围？
答：KCL定律：意时刻流入电路中节点电流恒等流出该节点电流0
KVL定律：意时刻电路中闭合回路绕行周段电压代数恒零0
6作线性电路分析中重定理简述叠加定理基容适范围？
答：包含电源线性电路电路某元件电流电压等电源单独作该元件产生电流电压代数叠加定理分析计算线性电路中电流电压计算功率
7电路分析计算中戴维南定理适宜应种情况？
答：果需计算电路中某支路电流时适宜采戴维南定理
8三素？行正弦交流电量瞬时波形图标出3素
答：幅值频率初相
9简述RLC串联电路产生串联谐振特点？
答：（1）电路阻抗呈电阻性 （2）电路中电流
（3）XLXC串联谐振电容电感两端产生高电压
10简述提高功率数意义？
答：电源够传送少功功率负载功率数cos直接关系cos1说明输出功率全部功功率电源设备充分利cos 说明电源设备容量利程度低功率数造成电源设备浪费
11三相交流电路中负载星形连接时相电流线电流相电压线电压关系？
答相电流线电流关系IPIL 相电压线电压关系ULUP
12三相交流电路中称负载三角形连接时相电流线电流相电压线电压关系？
答：相电流线电流关系ILIP 相电压线电压关系UPUL
13异步电动机起动求什？说明原
答：（1）足够起动转矩电动机克服负载转矩迅速旋转起 （2）起动电流太否会供电电网产生较电压降影响电网电气设备正常工作
14三相异步电动机调速方式种？
答：三种：（1）改变电源频率调速（2）改变转差率调速（3）异步电动机变极调速
15三相异步电动机控制方式种？
答：直接起动控制（点动长动）正反转控制时间控制行程控制
16果需电动机连续运行三相异步电动机功率选择注意什？
答：功率选择应该产生机械需实际功率选择效率功率数会低济选择电动机长时间工作外额定载状态仅保证正常工作造成电动机损坏
17三相鼠笼式异步电动机相较绕线式异步电动机优点什？
答：绕线式异步电动机优点转子回路中接入附加电阻改善电动机起动性起动转矩增起动电流减者调节异步电动机转速
18表示三相异步电动机起动力？三相异步电动机正常工作时电源电压允许波动范围少？
答：般异步电动机起动转矩额定转矩值Tqd TN 表示电动机起动力通常情况异步电动机起动力取值Tqd TN11~22间三相异步电动机正常工作时电源电压允许波动范围应该正常电压
19什控制电器？什低压电器？低压电器分两类？
答：谓控制电器指电路中起通断保护控制调节电器件控制电器中额定电压500V称低压控制电器低压控制电器分两类手动控制电器动控制电器
20接触器分两类？接触器功什？方？
答：接触器种动电器直流接触器交流接触器分功频繁接通断开交直流电路容量控制电路控制电动机电热设备电焊机等尤电力拖动系统中应广泛
21什正偏置反偏置？二极正偏置反偏置时分什状态？
答：PN结P区接电源正极N区接电源负极时称外加正电压正偏置P区接电源负极N区接电源正极时称外加反电压反偏置
正偏置时二极处导通状态反偏置时二极处截止状态
22稳压二极起稳压作？
答：稳压二极相普通二极较低反击穿电压特性曲线反击穿特性曲线陡击穿安全工作电流范围够保证电压变化串接限流电阻够稳压二极稳定工作指定反击穿区输出电压取稳压二极两端输入电压稳定情况稳压二极便起稳定输出电压作
23什说三极电流控制器件？
答：量控制角度基极电流控制信号变化够直流电源提供三极较量起控制作表现发射极集电极电流变化进行控制
24基放电路组成原什？
答：1．电路中直流通路交流通路 2．电路线性元件非线性器件组成
3．三极工作放状态保证信号失真超允许范围
25放电路信号源电阻RS输入电阻Ri电压放倍数影响？
答：信号源阻输入电阻分压作影响放电路信号源电阻RS越高电路电压放倍数越输入电阻Ri越高电路电压放倍数越
26什三极放电路饱失真截止失真？避免？
答：输入交流信号较静态工作点设置高信号正半周器件进入饱区造成波形失真称饱失真反静态工作点设置低信号负半周器件进入截止区造成波形失真称截止失真两种失真器件非线性特性造成统称非线性失真
避免出现饱失真截止失真调节电阻RBRC电源UCC静态工作点负载线移动改变负载线斜率静态工作点移合适位置
27分析计算运放电路时常三项理想化指标什？
答：（1）开环差模电压放倍数Aod穷（2）差模输入电阻Rid穷（3）差模输出电阻Rod零
28引入负反馈放电路性改善益处？
答：起稳定静态工作点提高放倍数稳定性改变输入输出电阻减失真拓展通频带等
29引入电压串联负反馈电流联负反馈放电路输入输出电阻分什影响？
答：引入电压串联负反馈会输入电阻增输出电阻减引入电流联负反馈会输入电阻减输出电阻增
30直流稳压电源般部分组成？
答：变压器整流电路滤波电路稳压电路四部分组成
31逻辑代数中应反演律原函数变反函数需进行互换？
答：三种互换：运算（·）运算（+）互换逻辑常量10互换原变量反变量互换（偶规进行两种互换需原反变量互换）
32 门非门余输入端应处理？门非门余输入端应处理？CMOS电路余输入端否允许悬空？
答：门非门电路余输入端应接低电位门非门余输入端应接高电位（TTL电路输入端悬空相高电位）CMOS电路输入端允许悬空
33 组合逻辑电路逻辑功电路结构特点什？
答：组合逻辑电路特点：逻辑功：输出时输入逻辑值关该时刻前输入电路状态均关称没记忆功电路结构构成组合逻辑电路门电路间没反馈环路
34 组合逻辑电路分析步骤什？
答：逻辑图中门输出端加标注写出门输出逻辑函数表达式门输出逻辑函数表达式进行迭代进行必化简写出真值表说明该电路途
35 结合图1电路图简述执行置位功程
答：置位称置1程：
置位功：S0R1时置位端效低电位非门U1输出高电位实现置位功Q1时非门U2两输入R1Q1输出Q0满足两输出互补条件
图1
36 型JK触发器CP升作动作特点？
答：型触发器称电位触发型方式动作特点：时钟CP升前刻瞬间JK接收输入信号求CP1期间输入状态保持稳定时钟降产生输出
37 边型JK触发器CP脉信号作动作特点？（分负边正边两种情形）
答：负边型（降触发型）：CP降前刻瞬间JK接收输入CP降产生输出正边型（升触发型）：CP升前刻瞬间JK接收输入CP升产生输出
38写出JK触发器特性方程确定述种情形输出次态（Qn＋1）
说明触发器应功
J1时Qn0时
K1时Qn1时
J0K0时初态Qn时
J1K1时初态Qn时
答：JK触发器特性方程：
Qn＋1JQn +KQn
J1时Qn0Qn＋1实现置位功
K1时Qn1Qn＋1 0实现复位功
J0K0时Qn＋1Qn实现保持功
J1K1时Qn＋1Qn实现翻转功
39 射极输出器特点
答：输出电压输入电压基相(似1略1)相位相输入电阻输出电阻
三综合题
1．已知正弦交流电流t0时值i(o)A已知初相角600试求
效值t01秒时值i(01)2A试求电流周期频率(8分)
解：瞬时值表达式
1图11示电路测量电源数值阻图中标出UR0组成某实际电压源已知R126ΩR255Ω开关K1闭合K2开时电流表读数2A开K1闭合K2读数1A试求UR0
•
R2
R1
R0
º
º
图11
•
U
K2
K1
º
º
解：K1闭合K2开I1（R0+R1）U
K1开K2闭合 I2（R0+R2）U
联立两式出 U58V R003Ω
2图12示电路中已知U1 U2 U32VR1 R2 R33Ω求UABUBCUCA少？
图12
R2
R1
R3
+
U2
+ U1
U3
+
解：设流ACB回路电流I根基尔霍夫定律
（R1+R2+R3）IU3U2+U1 求出IA
UABU1IR1V UBCU2IR22V UCAUABUBCV
3戴维南定理求图13电路中R5支路电流已知R1R2R4R55Ω
B
R310ΩU65V
D
C
A
R5
R4
R3
R2
R1
+
U
图13
解：断开R5求开路电压UO入端电阻R0
UBD U≈433V UCD U325V UBC UBD+UDCUBDUCD108V
U短路 R0（R1R3）+（R2R4）≈583Ω
求出电流I5 I5≈01A
4已知某正弦电压t0时值 u0110V初相600求效值
解：正弦电压瞬时表达式 uUmcos（ωt+600）
t0时 u0 Umcos600
Um220V U220V
5电感线圈接电压40V直流电源时测线圈电流4A接电压220V频率50HZ正弦交流电源时测电流10A求线圈电阻电感
解：直流电源作时 XLωL0R40410Ω
交流电源作时 Z22Ω
XL196Ω
L624mH
6图4示电路中已知电压表读数15V电流表读数1AR5Ω电源角频率ω200rads求电感L电路消耗功率
解：设电流参考相量I 00 A电阻R电压相量R
5 00 V电感电压超前电流相位900
UL1414V
XL1414Ω L70Mh PI2R5W
7已知RLC串联电路R10ΩL2mHC180pF电源电压5V求谐振频率f0谐振电流I0品质数Q0
º
•
UR
R
º
•
图4
LR
谐振频率 f02654KHZ
谐振电流 I005A
XLω0L3333Ω XC3333Ω Q0333
8已知交流信号源阻250欧姆通变压调变压器接25欧姆负载RL变压器初级等效电阻等信号源阻时信号源输出功率负载获功率问变压器变压应该少？
解：根K2变压器初级等效电阻R＇L K2RL25K2
变压器初级等效电阻等信号源阻时信号源输出功率：
R＇L K2RL25K2250
K2100
变压K10时负载获功率
9台三相异步电动机磁极数p2工作额定电压380V额定频率50Hz已知额定转速1450rmin求步转速额定转差率？
解：1）步转速n11500rmin
2）额定转差率sN0033
10台三相异步电动机额定功率10KW额定电压380V额定转速980rmin额定工作效率η95额定工作电流IN18A起动力系数15载系数22
求：1）电动机功率数
2）起动转矩Tqd转矩Tmax
解：1）电动机额定输入功率Kw
定子三相绕组：
电动机功率数091
2）额定转矩975Nm
起动力系数15起动转矩：
14618Nm
载系数22转矩
2144Nm
R
11图2示电路输入端加幅值10V正弦波电压试画出输出端电压u0波形设稳压D1D2稳压值均6V
+
+
º
•
º
D1
D2
u0
ui
º
•
º
图2
解：
67
0
67
t
t
u0
10
0
12 图1（a）（b）示电路中计二极正压降U12电压值少？
（a） 图1 （b）
解：图(a)U123V图(b)U126V
13基射放电路图3示已知：UCC＝67VRb300kWRc2kW三极β100rbb 300WUBE07VC1C2容量足够试求：
（1）静态工作点IBQ＝？ICQ＝？UCEQ＝？ （2）电压放倍数Au
图3
解：IBQ002mAICQ＝2mAUCEQ＝27V
AuβRC rbe－100´2´10316´103＝－125
14判断图4（a）（b）示电路否失真放交流信号说明原
（a） (b)
图4
解：图3（a）（b）示电路均失真放交流信号中图（a）中缺少基极偏置图（b）中缺少发射极电阻
15图5分压式偏置放电路图中4处错误请指出
º
UCC
•
RB1
C2
C1
•
º
•
º
RL
RB2
C3
•
•
•
•
º
º
解：（1）C3应接三极发射极端（2）发射极端需接REC3联（3）三极集电极应接电阻RC（4）电源电压UCC应正电压
16说明图6示电路种运算电路已知：R112kWRF18kW输入电压uI05V时试求输出电压值uO
图6
解：该电路反例运算电路uO－075V
Ui1
17图7（a）示运放具理想特性设两输入电压波形图7（b）士示试画出电压u0波形
1
0
1
t
R
R
Ui2
Ui1
•
º
∞
t
1
0
1
U0
º
Ui2
R
•
•
º
+
+
R
（a） 图7 （b）
解： 图示电路标准减法器直接运公式求：
t
u0
1
0
1
u0（ui2 ui1） ui2 ui1
画出输出波形图示
18图8示两级运放电路已知R1RF110kWR2R3RF220kWuI11VuI205V计算电路输出电压uO说明该电路够实现种功
图8
解：u005V该电路减法运算电路
19 三位二进制数码高位低位分送电路三输入端求三
位数码中奇数1时电路输出1否0试画出逻辑图
解：（1）根提出逻辑功求列出真值表表
A
B
C
F
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
1
0
1
0
0
1
（2）根真值表列写出函数表达式
F
式中
F
B⊕A⊕C
画逻辑图
F
C
B
A
1
1
表达式画出逻辑图图示两异门构成
20 根图示波形利非门画出实现逻辑功逻辑图
A
t
B
t
C
t
F
t
解：解 采正逻辑高电逻辑1低电逻辑0根波形列出真值表表
A
B
C
F
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
1
1
1
0
0
0
21图组合逻辑电路进行分析写出逻辑函数FIF2F3表达式指出逻辑功
解 ：FlA
F2B
F3 A十B
逻辑功实现两位二进制数较功
22 8线－3线优先编码器74148逻辑框图功表图示分析逻辑功
0
逻辑图 功表
（1） 输入输出效电位什？
（2） L表示低电位H表示高电位x表示高电位者低电位输入01234567xxxxxxL时输出A2A1A0值？相什十进制数？
（3） 输出A2A1A0LLH110＝(6)10相十进制数6时输入01234567值？
解：（1）答：根功表知输入输出均低电位效电位
（2）答：01234567xxxxxxL0000001输出A2A1A0LLL111＝(7)10相
十进制数7
（3）答：A2A1A0LLH110＝(6)10相十进制数6时输入01234567xxxxxLH00000107脚效高电位反映出优先编码器功
23中规模计数器74161构成计数电路图示设计数器初态0QDQCQBQA0000（1）绘出计数状态图（2）分析计数长度少？
解：设计数器初态0QDQCQBQA0000绘出计数状态图 0000>0001>0010>0011>0100>0101>0110>0111>1000>1001>1010>1011>
计数器循环计数状态7计数长度7七进制加法计数器
24 图二进制加法计数器74161构成计数电路构成八进制计数电路（1）设计数器初态0QDQCQBQA0000绘出计数状态图（2）完成电路正确连接
解：设计数器初态0QDQCQBQA0000绘出计数状态图
000>0001>0010>0011>0100>0101>0110>0111>1000>1001>1010>1011>
正确电路图见图示
请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄请您删容O(∩_∩)O谢谢2015年中央电期末复考试抄全电期末考试必备抄电考试必抄The battle for young viewers CCTV is embracing Internet culture and working with independent producers on TV shows to woo audiences under 35 Han Bing bin reports After charming audiences with his warm smile for 14 years China Central Television host Li Jiaming recently found himself targeted by a group of young netizens unhappy with his style The complaints came after Li hosted the premiere of Rising Star on Oct 31 It is a singing competition show that originated in Israel Many young netizens found his hosting style slow and boring and mocked it as CCTV evening gala style They even initiated an online campaign to replace him The 40yearold host＇s reaction to the criticism was surprising During the second episode he jokingly called himself the slow Jiaming and acted much younger talking faster and louder It＇s like selling a product When the customers file a complaint you must change says Li In the Internet age you get feedback very quickly These young people are so cute When you＇re willing to change for them they will quickly like you back In order to win more young viewers CCTV is relying on programs such as Rising Star to embrace Internet culture In Rising Star a studio audience and fans watching on television vote for their favorite singers in real time using the instantmessaging app WeChat Rising Star was designed to be a live broadcast but the Chinese version isn＇t because of policy reasons Still WeChat votes by viewers at home are still a major factor in determining which contestants advance to the next round In the show＇s latest episode more than 65 million votes were cast via WeChat Now the competition among entertainment shows is very fierce Audiences have more diverse needs CCTV needs to embrace an open attitude interact with young audiences and blend with the Internet says Lyu Yitao director of CCTV＇s entertainment channel The producer of Rising Star Enlight Media says the program will have a phenomenal effect given CCTV＇s audience base nationwide But it comes with a challenge says Zhang Hang chief producer of the program and CEO of Enlight Media＇s TV business Unlike topranking provincial satellite channels such as Hunan TV which have a large base of young fans thanks to a series of phenomenally popular entertainment and reality shows CCTV productions are usually more conservative and serious and thus have a much older audience base If we were to run this program on Hunan we may attract twice as many viewers says Zhang But since we didn＇t make it there we now have to make the best out of the given conditions And it means we have to make certain compromises When the current season of Rising Star ends Zhang says his company will conduct an overall evaluation of the program and make adjustments for future seasons Although audience ratings haven＇t lived up to Zhang＇s expectations he says the program has already helped CCTV attract more young people According to Enlight Media the number of people ages 15 to 35 who watched the first episode of Rising Star was 76 percent higher than the usual audience for CCTV entertainment productions In order to attract young audiences CCTV has been working with independent production companies As one of CCTV＇s closest partners Enlight Media has produced several entertainment and reality shows for the company＇s channels including the Chinese version of The Biggest Loser on CCTV＇s business channel and an original teenager talent show Shaonian Zhongguo－qiang (Strong Young Chinese) on CCTV1 This year CCTV also licensed EEMedia the producer of the popular Super Girl talent shows to produce the talk show Hi 2014 hosted by Taiwan pop star Harlem Yu and one of China＇s most popular TV stars Xie Na The show is geared toward younger audiences Canxing Productions which rose to fame with the success of its Voice of China series on Zhejiang TV also produced two talent shows for CCTV One is an original production called Songs of China which ended up as one of CCTV＇s most watched programs of 2014 The State Administration of Press Publication Radio Film and Television announced earlier this year that starting in 2015 only one music talent show can be aired nationwide during prime time each season and there can be only one program based on foreign formats each year However domestic media report that such policies don＇t apply to CCTV meaning it will become a highly desired platform by production companies Wang Changtian CEO of Enlight Media confirmed to the Shanghai Securities News that its programs scheduled to air on CCTV next year which include at least two reality shows won＇t be affected A kung futhemed reality show produced by Canxing is also reportedly scheduled to run on CCTV next year CCTV is very active The level of its acceptance of new ideas is even beyond my imagination says Zhang Hang Our cooperation with CCTV will surely continue When winter comes nothing is more relaxing than a hot spring bath For thousands of years natural mineralrich hot spring baths have also been used to relieve health ailments The water found in natural hot springs contains a variety of different minerals and the most common one is sulfur It has a rotten egg smell but is excellent for skin The sulfurcontaining water might be just what the doctor ordered when it comes to relieving pain stress itchy skin arthritis and more Hot springs resorts are thriving as biting cold winter arrives Here we take a look at some of the best natural hot springs China has to offer
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