电工基础试题(一)（Basic examination questions of Electrical Engineering ）

1、电工基础试题(一)（Basic examination questions of Electrical Engineering (1)）The basic questions of electrician (a).Txt to stay up late, because the courage to end the day; stay in bed because of the courage to start the day. A friend is to see through you who still love you. The national electrical network

2、operation of low-voltage part electrician foundation knowledge theory of licensing exam review questionsSome bloggers and Internet users should be invited to collect electrical knowledge review questions, examination, test centers and other blog published for users to borrow, electrical upgrade prom

3、otion exam, exam candidates, job training and examination, recertification examination of evidence, electrical network theory test work permit peace learning reference.Basic knowledge of electrical electrician is the foundation of all types, this paper selected questions, is the electrician foundati

4、on knowledge test content, but also an important content of the primary and intermediate electrician job training, the promotion examination. Familiar with and master the basic knowledge of electrical, allows you to further explore the mysteries of electrician or deal with all kinds of examinations

5、with ease, ease, relaxed and happy to finish the work. (the answer is only for reference, welcome the friends looking for carp, which may be wrong)From (and family)A choiceThe basic unit of charge is 1. (C).A. second B. amp C. Coulomb D. kgIs equal to 2.1 amperes (B) a.A. 103 B. 106 C. 109 D. 1023.

6、a uniform wire stretched for 3 times the original length, while the resistance to the original (C times).A. 3 B. 1/3 C. 9 D. 1/9The 4. generation of series resonant condition (C).A. XL, Xc B. XL Xc C. XL D. = Xc XL = Xc E. XL = XcAt the end of the 5. voltage no-load long HV transmission lines (B) en

7、d voltage.A. below B. is higher than C. equal to D. less than or equal to6. power three-phase symmetrical load, which is between the phase angle (B).The A. line voltage and line current B. phase voltage and line currentThe C. line voltage and phase current and phase voltage phase current D.7. when t

8、he power frequency increases, respectively with R, L bulb series, C3 circuit in parallel, and (B) increase the brightness of the bulb series.A. R B. L C. C D. R and L E. R and C8. of the rated voltage is 220V the light bulb in the 110V power supply, lighting power is the original (B).A. 2 B. 4 C. 1/

9、2 D. 1/49. the rated voltage of the same two resistors are connected in series in the circuit, the resistance of heat resistance (B).The same A. B. large C. small10. by using the principle of superposition calculation of complex circuit is a complex circuit to calculate circuit (A).A.Single supply B

10、. R, L D. C. large smallThe 11. circuit is composed of power supply, load, line (B).A. B. C. generator D. instrument transformer switch12. current is formed by the directional movement of electrons, accustomed to (D) directional movement direction as the direction of the current.A. B. C. N-S left ha

11、nd rule D. positive charge E. negative charge13, the current size of the current intensity to represent its value is equal to the per unit time through the conductor cross section (B) and algebra.A. B. electric current (charge) the strength of the current D. power C.The resistance of the 14. conduct

12、or, and the conductor section length not only relevant, but also with the conductor (D) on.A. B. C. D. material temperature humidity rangeThe three elements of 15. alternating current is the maximum frequency (C).A. B. C. D. the initial phase angle of phase voltage16. sinusoidal alternating current

13、effective value such as maximum value (D).A.1/3 B. 1/2 C. 2 D. 0.717. resistance resistance does not change with the applied voltage or current size of the call (C).A. B. fixed resistor variable resistor C. linear resistor D. nonlinear resistorResistance of 18. resistance change with the applied vol

14、tage or current size of the call (D).A. B. fixed resistor variable resistor C. linear resistor D. nonlinear resistor19. two parallel wires by currents in the same direction, between the conductor (D).A. B. C. eddy current magnetic field generated rejection D. attractThe 20. conductor in the current,

15、 more close to the conductor surface, (A), this phenomenon is called the skin effect.The greater the B. A. current voltage higher C. higher temperature resistance is D.21. power three-phase star connection or load line voltage is the voltage (A) times, line current and phase current. A. 3 B. 2 C. 1

16、v v D. 222. magnetic induction current generated by the (C) always try to change original flux.The influence of A. B. enhanced C. D. to prevent decay23. in the three-phase four wire system, when the three-phase unbalanced load, three-phase voltage equal, neutral current (B).A. B. is not equal to zer

17、o is equal to zero the increase of C. D. decreases24. voltage on the capacitor increasing process is an electric field in the capacitor, in this process, it absorb energy (C).A. B. C. D. power capacitor harmonic inductance25. in R, L, C series circuit, complex impedance Z= (D). r2 + l2c2 b. (r2l2) c

18、 c d.26. 串联谐振是指电路呈纯 (a) 性.a.电阻 b. 电容 c. 电感 d. 电抗27. 电容器在直流稳态电路中相当于 (b). 短路 b. 开路 c. 高通滤波器 d. 低通滤波器28.半导体的电阻随温度的升高 (c). 不变 b. 增大 c. 减小29.电场力做功与所经过的路径无关, 参考点确定后, 电场中各点的电位之值便惟一确定, 这就是电位 (c) 原理. 稳定 b. 不变 c. 惟一性 d. 稳压30.串联电路中, 电压的分配与电阻成 (a). 正比 b. 反比 c. 1: 1 to 2: 1.31.并联电路中, 电流的分配与电阻成 (b). 正比 b. 反比 c. 1

19、: 1 to 2: 1.32.线圈中感应电动势的放行可以根据 (c) 定律, 并应用线圈的右手螺旋定则来判定. 欧姆 b. 基儿霍夫 c. 楞次 d. 戴维南33.在纯电感电路中, 没有能量消耗, 只有能量 (c). 变化 b. 增强 c. 交换 d. 补充34.磁通的单位是 (b).a. b. wb c. t. d. mb and. f35. 串联电路具有以下特点 (c). 串联电路中各电阻两端电压相等 b. 各电阻上分配的电压与各自电阻的阻值成正比.c. 各电阻上消耗的功率之和等于电路所消耗的总功率 d. 流过每一个电阻的电流不相等36.电容器并联电路有如下特点 (a).in 每个电容两端

20、的电流相等. 并联电路的等效电容量等于各个电容器的容量之和 b.c. 并联电路的总电量等于最大电容器的电量 d. 电容器上的电压与电容量成正比37.对称三相电势在任一瞬间的 (d) 等于零. 频率 b. 波形 c. 角度 d. 代数和38.互感电动势的方向不仅取决于磁通的 (d), 还与线圈的绕向有关. 方向 b. 大小 c. 强度 d. 零增减39.导线和磁力线发生相对切割运动时, 导线中会产生成衣电动势, 它的大小与 () 有关. 电流强度 b. 电压强度 c. 方向 d. 导线有效长度40.The electric force in unit time is called power (

21、C).A. power B. power C. electric power D. power consumptionThe accuracy of D 41. current transformer is used to connect (C).A. measuring instrument B. indicator D. microcomputer protection instrument C. differential protectionA voltage transformer winding 42. turns (B) two times the number of windin

22、gs.A. is more than B. far greater than C. and less than D. far less than43. in the rectifier circuit (C) output DC ripple.A. single-phase half wave rectifier B. three-phase full wave rectifier C. three-phase bridge rectifier D. single-phase bridge rectifierIn the 44. plus rectifier filter capacitor,

23、 diode conduction is 1800 (B)A. is greater than B. and less than C.The 45. transistor base function (B) carrier.A. B. C. collection D. emission control amplifier46. NPN, PNP triode amplification, the emitter (B).A. reverse voltage B. with forward voltage C. NPN tube and PNP tube with forward voltage

24、, reverse voltage.D. PNP tube and NPN tube with forward voltage, reverse voltageThe 46. method is to solve the cutoff distortion amplifier (C).The increase of A. partial resistance B. decreases RC C. reduce the collector resistance bias resistor D. increases the lower resistanceThe control signal of

25、 47. bipolar transistor and field effect transistor (C) for.A. voltage B. current C. bipolar voltage, current field effectD. bipolar current to voltage, field effect48. three-phase load resistance half wave controlled rectifier circuit with the control, when the angle is greater than (D), the output

26、 current intermittent start.A. 300 B. 450 C. 600 D. 900Forward AC resistance 49. semiconductor diode with positive DC resistance of two size relations (C).A. B. C. is as small as big as the former than the latter the former than the latter in small D.50. high input impedance, low output impedance of

27、 the amplifier (B).A. common emitter amplifier B. emitter follower C. common base amplifierIs the main characteristics of 51. diodes (C).A. rectifier B. regulator C. unidirectional conduction D. reverse breakdown52. at the output end of the rectifier circuit and a capacitor, mainly using capacitance

28、 (C) characteristics, the ripple voltage becomes more stable.A. voltage mutation of B. filter C. D. boost charge dischargeGeneral layout of 53. electrical building on the map to be accurate to (A)A.厘米 B. 毫米 C. 微米 D. 分米54.建筑电气安装图一般用 (b) 表示.A. B. C. D. 大样图 三维立体图 立面图 平面图55.接线较复杂的图中, 导线连接用中断线表示, 通常采用 ()

29、 编号法.A. B. C. D. 逻辑 顺序 相对 绝对56.电气图中, 凡尺寸单位不用 (b) 的必须另外注明.A. B. C. D. 分米 微米 厘米 毫米57.在无特殊要求的情况下, 印刷板布线图中尺寸数字的单位为 (b).A. B. C. D. 分米 微米 厘米 毫米58.并列运行的变压器其容量之比一般不超过 (c).A 1: 1: 1, B 2 C 3: 1 D. 4: 159. 为防止分接开关故障, 应测量分接开关接头阻值, 其相差不超过 (d).A. B. C., 0.5%, 1%, 2% and 1.5% d.60. 油浸变压器在正常情况下为使绝缘油不致过速氧化, 上层油温不宜

30、超过 (b) .A. B. C. D. 105, 95, 85, 7561. 变压器绝缘自投入运行后, 在允许条件下运行, 其寿命可达 (b) 年.A. B. C. D. 1015 1520 2530 202562. 变压器运行中的电压不应超过额定电压的 (c).A. B. C. 2.0% 2.5% 5% d. 10%63. Y / yn0连接的变压器, 其中性线上的电流不应超过低压绕组额定电流的 (d)%.A. B. C. D. 25 15 10 564. 变压器在同等负荷及同等冷却条件下, 油温比平时高 (b) , 应判断变压器发生内部故障.A. B. C. D. 20 15 10 565

31、.当电网发生故障时, 如有一台变压器损坏, 其他变压器 (c) 过负荷运行.A. B. C. D. 允许1小时 允许短时间 不允许 允许2小时66.变压器的铁芯采用相互绝缘的薄硅钢片制造, 主要目的是为了降低 (c).A. B. C. D. 磁滞损耗 涡流损耗 杂散损耗 铜耗67.变压器并列运行时, 变比相差不超过 (b).A. B. 0.2% 0.5% C.1% + D + 1.5%68. power transformer short circuit voltage is the rated voltage (B).A. 2% to 4% B. 5% to 10% C. 11% to 15

32、% D. from 15% to 20%69. in the power system with kWh as the unit of measurement (B)A. voltage B. power C. power D. potential70. when the reference point change, the potential difference is a circuit (C).A. big B. small C. does not change D. cannot be determined71. an actual power supply voltage decr

33、eases with the load current (B).A. decreased and B. increased slightly lower C. invariant D.72. of Chinas current frequency is 50Hz, the period (B).A.0.01 B.0.02 C.0.1 D.0.273. (A) and the switch circuit is composed of four parts.A. power supply, load, generator, motor, wire connecting B. bus C. gen

34、erator, load and overhead lineD. motor, bulb, connecting wire74. reference point is also called the zero locus (A) which is composed of the.A. people decided D. earth nature determines the actual direction of C. potential of the B. reference direction75, the coil magnetic field direction judgment me

35、thod for (B).A. straight wire right B. helix C. left D. right hand rule rule generator76, the amplitude of sinusoidal alternating current (B).A. sinusoidal alternating current maximum value of 2 times the B. sinusoidal alternating current maximum C. sinusoidal alternating current waveform and the po

36、sitive and negativeD. sinusoidal alternating current maximum value of the times77. moving conductor cutting magnetic field lines generated maximum electromotive force when the angle between the conductor and the magnetic field lines should be (D).A. 0 B. 30 C. 45 D. 90The public 78. star connected t

37、hree-phase power supply is three-phase power supply (A).A. neutral B. reference point C. D. ground zero potential point79. an inductance coil connected to the AC circuit f=50Hz, inductance XL=50 Omega, if the power is connected to the f=150Hz, then XL (A) with inductanceA.150 B.250 C., 10 D.6080. an

38、 inductance coil connected to the AC circuit f=50Hz, inductance XL=50 Omega, if the power is connected to the f=10Hz, then XL (C) with inductanceA. 150 B. 250 C. 10 D. 6081. a capacitor connected to the AC circuit f=50Hz, capacitance Xc=240 Omega, if the power is connected to the f=150Hz, then Xc (A

39、) - capacitance.A. 80 B.120 C. 160 D. 72082。一电容接到F = 50hz的交流电路中，容抗XC = 240，若改接到F = 25hz的电源时，则容抗XC为（D）A. 80 b.120 C. 160 D. 48083。无论三相电路是Y连接或连接，当三相电路负载对称时，其总功率为（C）答：P = 3uicosB P = PU +光伏+ PW C P =3uicosD P =2uicos84。无论三相电路是Y连接或连接，也无论三相电路负载是否对称，其总功率为（B）答：P = 3uicosB P = PU +光伏+ PW C P =3uicos85纯电容电路的

40、电压与电流频率相同，电流的相位超前于外加电压为（C）。A./ 2 / 3B.C.条件D.86。纯电容电路的电压与电流频率相同，电流的相位超前于外加电压为8。纯电容电路的电压与电流频率相同，电流的相位超前于外加电压为（C）A. 60 B. 30 C. 90D. 18087三相电动势的相序为UVW称为（B）。A. B. C. D.反序零序正序负序88。在变电所三相母线应分别涂以（B）色，以示正相序A.红、黄、绿B.黄、绿、红C.绿、黄、红。89。正序的顺序是（一）A.你、V、W.B. V、U、W. C.你、W、诉D W、V、美元。二。判断题1。纯电阻单相正弦交流电路中的电压与电流，其瞬间时值遵循欧

41、姆定律（）。2。线圈右手螺旋定则是：四指表示电流方向，大拇指表示磁力线方向（）。3。短路电流大，产生的电动力就大（）。4。电位高低的含义，是指该点对参考点间的电流大小（）。5。直导线在磁场中运动一定会产生感应电动势（）。6。最大值是正弦交流电在变化过程中出现的最大瞬时值（）。7。电动势的实际方向规定为从正极指向负极（）。8。两个同频率正弦量相等的条件是最大值相等（）。9。在均匀磁场中，磁感应强度B与垂直于它的截面积的的乘积，叫做该截面的磁通密度（）10。自感电动势的方向总是与产生它的电流方向相反（）。11。一段电路的电压UAB = - 10V，该电压实际上是一点电位高于B点电位（）。12。正弦

42、量可以用相量表示，所以正弦量也等于相量（）。13。No no no current voltage current, no voltage. (*)14. if the positive power supply a 24V grounding potential anode is -24V. (V)15. potential two points in a circuit are V1=10V, V2=-5V, is the 1 point to 2 point 15V. voltage (V)16. a bar magnet off a section is a bar magnet, i

43、t still has two poles (V).The 17. magnetic field lines to describe the direction is always from the magnet in magnetic N pole to S pole (x).18. in electromagnetic induction, inductive current and electromotive force exist at the same time; no induction current, no induction electromotive force (x)Th

44、e relationship between cycle and frequency of 19. angle sinusoidal alternating current is the reciprocal (x).20. there are two different frequency and initial phase of sinusoidal AC voltage U1 and U2, if their effective values are the same, the maximum value (x) are the same.The current phase of the

45、 AC voltage across the resistor and the 21. resistor in the same resistance, current and voltage proportional to (V).The 22. is the apparent power, active power and reactive power (x) plus.23. sinusoidal alternating current angle in frequency is the frequency of alternating current (x).24. load powe

46、r is positive load to absorb energy, the current and voltage drop of the actual direction. (V)25. people used the load refers to the amount of power load, the voltage to a load, refers to the current through the load size. (V)26. through the current resistance increases to 2 times of the original el

47、ectric power consumption, it also increases to 2 times the original. (*)27. the voltage on resistance increases to 2 times of the original electric power consumption, it also increases to 2 times the original. (*)28. a number of series resistance, the resistance is small, the current is small. (*)Th

48、e equivalent resistance of the 29. resistor when the value is smaller than the minimum value of resistance. (V)The 30. capacitor C is determined by the voltage of the capacitor. (*)31. symmetrical three-phase Y connection circuit, the line voltage is 3 times the maximum RMS voltage. (*)The current p

49、hase of the AC voltage across the resistor and the 32. resistor in the same resistance, current and voltage is proportional to the. (*)The 33. is the apparent power, active power and reactive power plus. (*)The voltage between the phase line voltage is 34. (V)The voltage is 35. phase line and the ze

50、ro line between phase voltage.36. star connected three-phase load, line current is equal to phase. (V)37. phase load for a delta connection when the line voltage is equal to phase voltage. (V)38. alternating current of lead and lag, only on the same frequency, without frequency alternating current,

51、can not be said to lead and lag ()39. pure inductance coil DC, equivalent to short circuit. (V)40. three-phase supply connected in three-phase four wire system, the purpose is to provide two kinds of voltage to load in low voltage distribution system, the standard voltage regulation line voltage 380V, phase voltage of 220V. (V