Source of question bank: Safety production mock examination, WeChat public account mini program
The 2021 electrician (primary) exam platform and electrician (primary) mock exam question bank, including the answers and analysis of the electrician (primary) exam platform and electrician (primary) mock exam question bank exercises. Combining the latest syllabus of the national electrician (primary) exam and the summary of the real questions of the electrician (primary) exam from the public account of the safety production simulation test, it is helpful for the practice of the electrician (primary) simulation exam question bank.
1. [True and True] () When measuring current, select an ammeter with an appropriate range according to the current size, and the current cannot be greater than the maximum range of the ammeter. (√)
2. [True/True Questions] The square is a measuring tool for measuring right angles and a guiding tool for drawing parallel and vertical lines. ()( ×)
3. [True/True] () For capacitors used in series, the capacitors with small capacity can withstand high voltages. (√)
4. [True and True] The voltage direction is always consistent with the current direction () (×)
5. [Judgement Questions] () The work ticket is issued by the superior. (×)
6. [True/True Question] () If conditions permit, it is ideal to use a constant temperature electric soldering iron. (√)
7. [True and True] () Parallel appropriate capacitors at both ends of the inductive load can reduce the reactive power supplied to the load by the power supply. (√)
8. [True/True] () Emitter follower is a typical voltage series negative feedback amplifier circuit. (√)
9. [True and True] () Current whose size and direction do not change with time is called steady DC. (√)
10. [True/Treatment] The main bimetal strip of the thermal relay and the bimetal strip as the temperature compensation element have opposite bending directions. () (√)
11. [True and True] () The setting current of the thermal element of the thermal relay is generally adjusted to 0.95 to 1.05 times of the rated current of the motor. (√)
12. [True and True] The iron loss is constant when the transformer is running. () (√)
13. [True/True] () When connecting the wires in the terminal in the junction box, be sure to wrap the insulating tape. (×)
14. [True/True Question] () When laying the 4mm2 BLV aluminum core plastic wire in the open, its safe current carrying capacity is 30A at room temperature 30℃. (√)
15. [Judgment] The purpose of the three-phase asynchronous motor series resistance step-down starting is to improve the power factor. ()( ×)
16. [True and True] () Plastic pipe wiring is used in places that are corrosive but not explosive or mechanically damaged. (√)
17. [True or True] () The residual flux of organic flux is easy to remove. (√)
18. [True/True] () Whether it is a working day or a rest day, it is an encouraged good dressing habit to wear work clothes. (×)
19. [True and True] () For circuits where the motor does not start frequently and the starting time is not long, the rated current of the melt is greater than 1.5 times the rated current of the motor. (×)
20. [True and True] () Zener diode voltage regulator circuit is to connect the voltage regulator tube and the load in parallel. (√)
21. [Judgment] () Common faults of three-phase asynchronous motors include: motor overheating, motor vibration, low speed or low torque after the motor starts. (√)
22. [True and True] () For circuits where the motor does not start frequently and the start-up time is not long, the rated current of the melt is approximately equal to 1.5 times the rated current of the motor. (√)
23. [True and True] () Commonly used line pipes include water gas pipes, electrical wires, polyvinyl chloride pipes, flexible polyvinyl chloride pipes, self-extinguishing plastic wire pipes, metal hoses and porcelain pipes. (√)
24. [True and True] () Pole pits are divided into circular pits and trapezoidal pits. For poles without chuck and chassis, they are usually dug into trapezoidal pits. (×)
25. [True and True] () Drilling is a processing method of drilling holes in materials or workpieces with a drill. (√)
26. [True/True] () Generally, insulation clamps are not used in power systems above 35KV. (√)
27. [True and True] () The layout of general lighting lamps usually adopts two schemes: uniform layout and selective layout. (√)
28. [Single-choice question] When laying electric wires, when the length of the pipeline exceeds (), a junction box or junction box should be installed in the middle of the pipeline. (D)
A、12m
B、20m
C 、 30m
D、45m
29. [Single-choice question] If there is a normal working current in the circuit, the state of the circuit is () (C)
A, short circuit
B. Open
C. Access
D. Any state
30. [Single-choice question] When the cross section of the duralumin busbar is 50F5 and below, the bending radius of flat bend is () times its thickness. (C)
A、1
B、1.5
C、2
D、2.5
31. [Single-choice question] The working state of the transistor in the cut-off state is (). (B)
A. The shoot junction is forward biased, and the collector junction is reverse biased
B. The shoot junction is reverse biased, and the collector junction is reverse biased
C. The shoot junction is forward biased, and the collector junction is forward biased
D. The shoot junction is reversely biased, and the collector junction is forward biased
32. [Single-choice question] Call the number of magnetic lines perpendicular to a certain section of the magnetic field as (). (A)
A. Magnetic flux or magnetic flux
B. Magnetic induction
C. Magnetic permeability
D. Magnetic field strength
33. [Single-choice question] A single-phase half-wave rectifier inductance filter circuit, the DC voltage of the load is known to be 4.5, then the secondary voltage of the power transformer of the circuit is () volts. (A)
A、10
B、20
C、5
D、15
34. [Single-choice question] In the electrical diagram, the main circuit is represented by the () line. (B)
A, dotted line
B, thick solid line
C, thin solid line
D, thick dotted line
35. [Single choice] The method of changing the direction of the capacitive single-phase asynchronous motor is (). (D)
A. Swap the main and auxiliary windings
B. Swap the power phase line and the neutral line
C. Capacitor wiring swap
D. Any one of the main winding or the auxiliary winding is reversed end to end
36. [Single-choice question] The grounding body is mostly made of (), and its section should meet the requirements of thermal stability and mechanical strength. (C)
A. Any metal material
B. Copper and aluminum materials
C, section steel
D, insulated wire
37. [Single-choice question] The following () is not the main parameter of the transistor. (D)
A. The maximum allowable collector current ICm
B. Maximum allowable power loss of collector
C, penetration current
D. Trigger voltage
38. [Single-choice question] Single-phase half-wave rectifier circuit, after adding capacitor filter, the highest reverse voltage that the rectifier diode will bear will be (). (C)
A, unchanged
B. Lower
C, elevated
D. The single-phase half-wave rectifier circuit is the same
39. [Single-choice questions] Capacitor filter circuits generally use large-capacity () capacitors. (A)
A. Electrolysis
B. Ceramics
C, mica
D, metalized paper
40. [Single-choice question] The minimum cross-section of the core of the insulated wire laid through the pipe, the copper wire is (). (A)
A、1
B、1.5
C、2.5
D、4
41. [Single-choice question] Pure inductance components are equivalent to () in DC circuits. (C)
A. Open
B. Components with large impedance
C, short circuit
D. Components with large inductance
42. [Single-choice question] The main purpose of power transformers is (). (B)
A. Transform impedance
B. Conversion voltage
C. Change the phase
D. Change frequency
43. [Single-choice question] 2DW7A means () diode. (B)
A, glow
B. Voltage stabilization
C, photosensitive
D, variable volume
44. [Single choice] When installing the screw fuse, the power cord must be connected to the () terminal of the porcelain base. (D)
A, left
B, right
C, on
D, down
45. [Single choice] The voltage waveform of the rectifier element of the inductance filter circuit and the voltage waveform of the load (). (B)
A, the same
B. Different
C, approximate
D, irrelevant
46. [Single-choice questions] The main categories of soft magnetic materials include ferrite soft magnetic materials, (), and other soft magnetic materials. (D)
A, stainless steel
B. Copper alloy
C, aluminum alloy
D. Metal soft magnetic materials
47. [Single-choice question] Three resistors R1, R2, and R3 are connected in series on a DC power supply, and the relationship of the three resistors is known to be R1>R2>R3, then their assigned voltage relationship is (). (B)
A、U1＝U2＝U3
B、U1＞Ｕ2＞Ｕ3
C、Ｕ1＜Ｕ2＜Ｕ3
D、Ｕ2＞Ｕ1＞Ｕ3
48. [Single choice] Among the following starting methods of three-phase asynchronous motors, the best performance is (). (C)
A. Start directly
B. Decompression start
C. Frequency conversion start
D. Pole-changing start
49. [Single choice] Wire cutters (electrician's pliers) can be used to cut (). (A)
A. Thin wire
B. Glass tube
C, copper bar
D. Water pipe
50. [Single-choice question] The function of transformer impedance transformation is often used in () occasions. (D)
A. Low-voltage power distribution
B. High-voltage power transmission
C. Power amplification
D, impedance matching
The above is the 2021 electrician (primary) exam platform and electrician (primary) mock exam question bank. Support the precision electrician (primary) examination questions in all regions of the country, and support the exercises of the safety qualification certificate, special operation certificate, vocational skill appraisal and other work types.