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Khoa khoa häc c¬ b¶n
Bé m«n: Ngo¹i ng÷
ng©n hµng c©u hái thi kÕt thóc häc phÇn
häc phÇn: tiÕng anh kü thuËt
(3 tÝn chØ)
Dïng cho ®µo t¹o bËc ®¹i häc theo häc chÕ tÝn chØ
c¸c ngµnh ®iÖn vµ ®iÖn tö
Th¸i nguyªn – 8/2007
1. NỘI DUNG ĐÁNH GIÁ THI KẾT THÚC HỌC PHẦN
UNIT 1: Conductors, insulators and semiconductors
Reading:
- True or False
- Rephrasing
- Contextual reference
- Summarizing
Use of language:
- Description of shapes, positions and connections, experiments
- Relative clauses
- Passive voice
Writing:
- Writing instructions
- Sentence / Paragraph building
UNIT 2: Circuit elements
Reading:
- True or False
- Rephrasing
- Contextual reference
- Summarizing
Use of language:
- Description of function, purpose
- Relative clauses
Writing:
- Sentence / Paragraph building
UNIT 3: The dc motor
Reading:
- Contextual reference
- Note-taking
Use of language:
- Description of positions, components
- Relative clauses
- Comparison and contrast
Writing:
- Sentence building
- Writing impersonal instructions
UNIT 4: The cathode ray tube
Reading:
- Contextual reference
- Note-taking
Use of language:
- Description of a process, sequence, distribution of power
- Short relative clauses
UNIT 5: Process control systems
Reading:
- Contextual reference
- Reading for specific information
- Note-taking
Use of language:
- Cause and Effect
Writing:
- Sentence building
UNIT 6: Logic gates
Reading:
- Finding out facts
- Summarizing
Use of language:
- Making predictions
Writing:
- Grouping sentences
2. PHƯƠNG PHÁP ĐÁNH GIÁ
- Tự luận
- Hình thức thi viết (thời gian:90’)
3. NGUYÊN TẮC TỔ HỢP CÂU HỎI ĐỂ LÀM ĐỀ THI KẾT THÚC HỌC PHẦN
- Nguyên tắc:
+ Kết hợp giữa các phần câu hỏi
+ Một đề thi bao gồm 4 loại câu hỏi: 6 câu loại 1, 4 câu loại 2, 6 câu loại 3, 5
câu loại 4.
+ Câu hỏi loại 3 được tổ hợp từ các loại 3a, 3b, 3c; mỗi loại 2 câu
- Thang điểm:
+ Câu hỏi loại 1: 3 điểm (6 câu hỏi đọc hiểu, mỗi câu 0,5điểm)
+ Câu hỏi loại 2: 0,25 điểm
+ Câu hỏi loại 3: 0,5 điểm
+ Câu hỏi loại 4: 0,5 điểm
- Loại câu hỏi:
+ Câu hỏi loại 1: Read the following passage and answer the questions below.
+ Câu hỏi loại 2: Choose the best word to fill in the gaps.
+ Câu hỏi loại 3: Rewrite the following sentences without changing the meanings.
+ Câu hỏi loại 4: Give the correct form of the word in brackets.
4. NGÂN HÀNG CÂU HỎI
4.1.Câu hỏi loại 1
1. ELECTRIC MOTOR
An electric motor converts electrical energy into mechanical energy. The reverse process, that
of converting mechanical energy into electrical energy, is accomplished by a generator or
dynamo. Traction motors used on locomotives often perform both tasks if the locomotive is
equipped with dynamic brakes. Electric motors are found in household appliances such as
fans, refrigerators, washing machines, pool pumps and fan-forced ovens.
Most electric motors work by electromagnetism, but motors based on other electromechanical
phenomena, such as electrostatic forces and the piezoelectric effect, also exist. The
fundamental principle upon which electromagnetic motors are based is that there is a
mechanical force on any current-carrying wire contained within a magnetic field. The force is
described by the Lorentz force law and is perpendicular to both the wire and the magnetic
field. Most magnetic motors are rotary, but linear motors also exist. In a rotary motor, the
rotating part (usually on the inside) is called the rotor, and the stationary part is called the
stator. The rotor rotates because the wires and magnetic field are arranged so that a torque is
developed about the rotor's axis. The motor contains electromagnets that are wound on a
frame. Though this frame is often called the armature, that term is often erroneously applied.
Correctly, the armature is that part of the motor across which the input voltage is supplied.
Depending upon the design of the machine, either the rotor or the stator can serve as the
armature.
Questions:
1. What is the function of an electric motor?
2. Where are electric motors found?
3. What is the fundamental principle upon which electromagnetic motors are based?
4. How is the force described by Lorentz force law?
5. What is the rotating part called and what is the stationary part called?
6. Is the armature the rotor or the stator?
2. Stepper motors
Closely related in design to three-phase AC synchronous motors are stepper motors, where an
internal rotor containing permanent magnets or a large iron core with salient poles is
controlled by a set of external magnets that are switched electronically. A stepper motor may
also be thought of as a cross between a DC electric motor and a solenoid. As each coil is
energized in turn, the rotor aligns itself with the magnetic field produced by the energized field
winding. Unlike a synchronous motor, in its application, the motor may not rotate
continuously; instead, it "steps" from one position to the next as field windings are energized
and de-energized in sequence. Depending on the sequence, the rotor may turn forwards or
backwards.
Simple stepper motor drivers entirely energize or entirely de-energize the field windings,
leading the rotor to "cog" to a limited number of positions; more sophisticated drivers can
proportionally control the power to the field windings, allowing the rotors to position
"between" the "cog" points and thereby rotate extremely smoothly. Computer controlled
stepper motors are one of the most versatile forms of positioning systems, particularly when
part of a digital servo-controlled system.
Stepper motors can be rotated to a specific angle with ease, and hence stepper motors are used
in pre-gigabyte era computer disk drives, where the precision they offered was adequate for
the correct positioning of the read/write head of a hard disk drive. As drive density increased,
the precision limitations of stepper motors made them obsolete for hard drives, thus newer
hard disk drives use read/write head control systems based on voice coils.
Questions:
1. To what are stepper motors closely related in design?
2. Why does the rotor align itself with the magnetic field produced by the energized field
winding?
3. Does the motor rotate continuously?
4. What are one of the most versatile forms of positioning systems?
5. Where are stepper motors are used?
6. What are the read/write head control systems of newer hard disk drives based on?
3. Dynamo
The Dynamo was the first electrical generator capable of delivering power for industry. The
dynamo uses electromagnetic principles to convert mechanical rotation into an alternating
electric current. A dynamo machine consists of a stationary structure which generates a strong
magnetic field, and a set of rotating windings which turn within that field. On small machines
the magnetic field may be provided by a permanent magnet; larger machines have the
magnetic field created by electromagnets.
The first dynamo based on Faraday's principles was built in 1832 by Hippolyte Pixii, a French
instrument maker. It used a permanent magnet which was rotated by a crank. The spinning
magnet was positioned so that its north and south poles passed by a piece of iron wrapped with
wire. Pixii found that the spinning magnet produced a pulse of current in the wire each time a
pole passed the coil. Furthermore, the north and south poles of the magnet induced currents in
opposite directions. By adding a commutator, Pixii was able to convert the alternating current
to direct current.
Unlike the Faraday disc, many turns of wire connected in series can be used in the moving
windings of a dynamo. This allows the terminal voltage of the machine to be higher than a
disc can produce, so that electrical energy can be delivered at a convenient voltage.
The relationship between mechanical rotation and electric current in a dynamo is reversible;
the principles of the electric motor were discovered when it was found that one dynamo could
cause a second interconnected dynamo to rotate if current was fed through it.
Questions:
1. What was the first electrical generator capable of delivering power for industry?
2. What does a dynamo machine consist of?
3. When was the first dynamo based on Faraday's principles built?
4. What provides the magnetic field on small machines?
5. How was the spinning magnet positioned?
6. What is the purpose of the commutator?
4. Digital electronics
Digital electronics are those electronics systems that use a digital signal instead of an analog
signal. Digital electronics are the most common representation of Boolean algebra and are the
basis of all digital circuits for computers, mobile phones, and numerous other consumer
products.
The most common fundamental unit of digital electronics is the logic gate. By combining
numerous logic gates (from tens to hundreds of thousands) more complex systems can be
created. The complex system of digital electronics is collectively referred to as a digital
circuit.
To most electronic engineers, the terms "digital circuit", "digital system" and "logic" are
interchangeable in the context of digital circuits.
Advantages of Digital electronics
The usual advantages of digital circuits when compared to analog circuits are:
- Digital systems interface well with computers and are easy to control with software. It is
often possible to add new features to a digital system without changing hardware, and to do
this remotely, just by uploading new software. Design errors or bugs can be worked-around
with a software upgrade, after the product is in customer hands.
- Information storage can be much easier in digital systems than in analog ones. In particular,
the great noise-immunity of digital systems makes it possible to store data and retrieve it later
without degradation. In an analog system, aging and wear and tear will degrade the
information in storage, but in a digital system, as long as the wear and tear is below a certain
level, the information can be recovered perfectly.
Questions:
1. What are digital electronics?
2. How can more complex systems be created?
3. Is the complex system of digital electronics collectively referred to as a digital circuit ?
4. How many advantages mentioned in the text do digital circuits have when compared to
analog circuits?
5. What can design errors or bugs be worked-around with?
6. When can the information be recovered perfectly?
5. Circuit breaker
A circuit breaker is an automatically-operated electrical switch designed to protect an
electrical circuit from damage caused by overload or short circuit. Unlike a fuse, which
operates once and then has to be replaced, a circuit breaker can be reset (either manually or
automatically) to resume normal operation. Circuit breakers are made in varying sizes, from
small devices that protect an individual household appliance up to large switchgear designed
to protect high voltage circuits feeding an entire city.
Types of circuit breaker
There are many different technologies used in circuit breakers and they do not always fall into
distinct categories. Types that are common in domestic, commercial and light industrial
applications at low voltage (less than 1000 V) include:
- MCB (Miniature Circuit Breaker)— rated current not more than 100 A. Trip characteristics
normally not adjustable. Thermal or thermal-magnetic operation.
- MCCB (Moulded Case Circuit Breaker)— rated current up to 1000 A. Thermal or thermal-
magnetic operation. Trip current may be adjustable.
Electric power systems require the breaking of higher currents at higher voltages. Examples of
high-voltage AC circuit breakers are:
- Vacuum circuit breaker—With rated current up to 3000 A, these breakers interrupt the
current by creating and extinguishing the arc in a vacuum container. These can only be
practically applied for voltages up to about 35,000 V, which corresponds roughly to the
medium-voltage range of power systems. Vacuum circuit breakers tend to have longer life
expectancies between overhaul than do air circuit breakers.
- Air circuit breaker—Rated current up to 10,000 A. Trip characteristics are often fully
adjustable including configurable trip thresholds and delays. Usually electronically controlled,
though some models are microprocessor controlled via an integral electronic trip unit. Often
used for main power distribution in large industrial plant, where the breakers are arranged in
draw-out enclosures for ease of maintenance.
Questions:
1. What is the function of a circuit breaker?
2. What is the difference between a circuit breaker and a fuse?
3. What are the types of circuit breakers at low voltage (less than 1000 V) mentioned in the
text?
4. What requires the breaking of higher currents at higher voltages?
5. How do vacuum circuit breakers interrupt the current?
6. What is the rated current of air circuit breakers?
6. Digital-to-analog converter
In electronics, a digital-to-analog converter (DAC or D-to-A) is a device for converting a
digital (usually binary) code to an analog signal (current, voltage or electric charge). Digital-
to-analog converters are interfaces between the abstract digital world and analog real life.
Applications of a digital-to-analog converter
- Audio
Most modern audio signals are stored in digital form (for example MP3s and CDs) and in
order to be heard through speakers they must be converted into an analog signal. DACs are
therefore found in CD players, digital music players, and PC sound cards.
Specialist stand-alone DACs can also be found in high-end hi-fi systems. These normally take
the digital output of a CD player (or dedicated transport) and convert the signal into a line-
level output that can then be fed into a pre-amplifier stage. Some of these can also be made to
interface with computers using a USB interface.
- Video
Video signals from a digital source, such as a computer, must be converted to analog form if
they are to be displayed on an analog monitor. As of 2007, analog inputs are more commonly
used than digital, but this may change as flat panel displays with DVI and/or HDMI
connections become more widespread. A video DAC is, however, incorporated in any Digital
Video Player with analog outputs. The DAC is usually integrated with some memory (RAM),
which contains conversion tables for gamma correction, contrast and brightness, to make a
device called a RAMDAC.
Questions:
1. What is the function of a digital-to-analog converter ?
2. Which field is a digital-to-analog converter applied?
3. How are most modern audio signals stored?
4. What does These mean?
5. What must be done if video signals from a digital source are to be displayed on an analog
monitor?
6. What is a RAMDAC?
4.2 Câu hỏi loại 2
1. ……………. is usually measured in microfarads or picofarads.
2. ……………. are used in temperature-sensing devices.
3. If we connect a battery across a body, there is a ………….. of free electrons towards the
positive end.
4. ………… are midway between conductors and insulators.
5. A ………….. is an instrument which is used for measuring small currents.
6. All ………..contain four elements: a source, a load, a transmission system and a control.
7. A lamp changes ………… energy into light and heat.
8. A ………..current flows in one direction only.
9. An electric motor is a machine for converting electrical energy into ……………..energy.
10. A resistor is a device which is used to add ..................to a circuit.
11. Under certain……….., semiconductors allow a current to flow easily but under others they
behave as insulators.
12. Copper is used for cables because it is a good………….. .
13. A cathode-ray-tube screen glows when an electron………… strikes it.
14. The ……………… of metals varies with their temperature.
15. A solar cell is an electric cell which converts ………. into electrical energy.
16. Common ……….. devices are AND, NOR and NAND gates and inverters.
17. A …. gate is an electronic switching device which responds to two levels of input: a high
level represented by 1 and a low level represented by 0.
18. ………… circuits contain four diodes: two conduct in the positive half and two conduct in
the negative half of each cycle.
19. The basic components of a ……….. system are an input transducer, an error sensor, a
controller and an output transducer.
20. The CRT comprises an electron ……… and a deflection system enclosed in a glass tube
with a phosphor coated system.
21. The DC motor operates on the principle that when a current-carrying conductor is placed
in a magnetic …….., a force is produced on the conductor.
22. Two methods of MHD generation can be used: the open-cycle and the………… .
23. Current moves from a point of high potential energy to one of ………… potential.
24. Motors can be designed to run on direct or …………. current.
4.3 Câu hỏi loại 3
I. Loại 3a
1. The coil is connected in series with a resistor. The resistor has a value of 240Ω.
→ The coil
2. Carbon resistors are made of compressed graphite. The graphite is formed into small tubes.
→ Carbon resistors
3. An alternating current changes from positive to negative in each cycle. This cycle is
repeated 50 or 60 times per second in most AC systems.
→ An alternating current
4. Leaking electrolyte may damage the equipment. The cells are installed in the equipment.
→ Leaking electrolyte
5. The error sensor output is fed to the controller. The controller sends a signal to the power
supply of the motor.
→ The error sensor output
6. A simple controller is an electromagnetic relay. It uses a small signal to control a much
larger signal such as a power supply output.
→ A simple controller
7. On leaving the electron gun, the beam passes through two sets of plates. These plates are at
right angles to each other.
→ On leaving the electron gun, the beam
II. Loại 3b
1. The electrolysis of salt water generates chlorine.
→ Chlorine
2. We use thermistors in temperature-sensing devices because their resistance falls rapidly as
their temperature rises.
→ Thermistors
3. We connect the negative pole of the battery to earth.
→ The negative pole
4. A circuit breaker can protect circuits from excessive currents.
→ Circuits
5. Manufacturers can design motors to run on direct or alternating current. → Motors
6. Springs hold carbon brushes in contact with the commutator.
→ Carbon brushes
III. Loại 3c
1. All circuits contain four elements: a source, a load, a transmission system and a control.
→ All circuits consist
2. Semiconductors have replaced valves in most applications but they are still used in large
transmitters.
→ Although
3. The CRT comprises an electron gun and a deflection system enclosed in a glass tube with a
phosphor coated screen.
→ The CRT is made up
4. The commutator consists of a number of copper segments insulated from one another.
→ The commutator is composed
5. The resistance of thermistors falls rapidly as their temperature rises. They are therefore used
in temperature-sensing devices.
→ Thermistors are used
6. Transistors can be damaged by heat. Care must be taken when soldering transistors.
→ Care must be
7. Pure water does not conduct well so sulphuric acid has to be added before the electrolysis
takes place.
→ Because
8. A ceramic coating is applied over the winding. The ceramic coating insulates the winding.
→ A ceramic coating is applied over the winding to
4.4 Câu hỏi loại 4
Electric current The movement of free electrons towards the positive end
Conductors Materials which provide an easy path for an electric current
Insulators Materials which do not easily release electrons
Semiconductors Materials which are midway between conductors and
insulators
Miliammeter An instrument which is used for measuring small currents
Lamp A kind of load which changes electrical energy into light
and heat
Generator A device which converts mechanical energy into electrical
energy
Alternating current A current which flows first in one direction, then in the
other
Direct current A current which flows in one direction only
Resistor A device which is used to add resistance to a circuit
Light meter An instrument which measures light
Ammeter An instrument which measures current
Electric motor A device which converts electrical energy into mechanical
energy
Electrolysis A process in which an electric current can separate a
chemical compound into its components.
Solar cell An electric cell which converts sunlight into electrical
energy
DC motor A machine which runs on direct current and is used to
convert electrical energy into mechanical energy
Capacitance A quantity which is measured in farad, microfarad or
picofarad
Battery A device which changes chemical energy into electrical
energy
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