Санкт-Петербургское государственное бюджетное профессиональное образовательное учреждение "Санкт-Петербургский технический колледж управления и коммерции"
Английский язык
Методическая разработка по теме
«Пассивные элементы электрической цепи»
для студентов 3курса учреждений среднего профессионального технического образования
подготовила
Апурина Любовь Кирилловна
преподаватель
иностранного языка
Санкт-Петербург
2021 г
В данная методическая разработка предназначена для студентов 3 курса образовательных учреждений среднего профессионального образования, обучающихся по инженерно-техническим специальностям.
Для проработки темы предлагаются небольшие тексты и задания к ним.
Материал соответствует требованиям Федерального государственного образовательного стандарта среднего профессионального образования и профессиональным требованиям.
Basic elements of electric circuits.
The three basic elements used in electronic circuits are the resistor, capacitor, and inductor. They each play an important role in how an electronic circuit behaves. They also have their own standard symbols and units of measurement
Active vocabulary
restrict - ограничивать
flow - поток
electric current – электрический ток
resistance - сопротивление
amount - количество
determine - определить
equation - равенство
voltage - напряжение
inversely - обратно
Restricting the flow of electrons or electric current to a certain level is called resistance and the device or component used to restrict the electric current is called resistor.
The amount of electric current restricted by the resistor is determined by using the Ohm’s Law equation.
where R = Resistance, V = Voltage, I = Electric current
The electric current flowing through a resistor is inversely proportional to the resistance of a resistor and directly proportional to the voltage applied across the resistor.
In other words, the amount of electric current flowing through the resistor decreases with increasing the resistance of a resistor (if voltage applied across resistor is kept constant) and increases with increasing the voltage applied across the resistor (if resistance of a resistor is kept constant) .
Georg Simon Ohm
(16 March 1789 – 6 July 1854)
Discovered the relationship between voltage and current in electrical circuits “Ohm's Law”.
Put the words in the correct order
electric/ the amount/ the resistance / decreases/ current /of a resistor/increasing / with
Complete the following sentences:
1 According to
Ohm's Law, current equals the voltage divided by the …… .
a. Power
b. Resistor
c. Constant
d. Resistance
e. Circuit
2 If voltage applied across resistor is kept constant and the resistance of a resistor grows the electric current flowing through the resistor …… .
a decreases
b kept constant
c increases
d restricts
3 Resistor is a device that is used to …… .
a restrict the electric current
b decrease the voltage
c determine the electric current
Active vocabulary
hence - следовательно
reduce – уменьшить
circuit – cхема
Insulator - изолятор
conductor - проводник
whereas – в то время как
сross sectional area – площадь поперечного сечения
сollide - сталкиваться
What is resistor?
Resistors are the most commonly used electronic components in the circuits. A resistor is an electronic component that reduces or restricts the flow of electrons or electric current to certain level.
How much electric current does a resistor blocks is depends on the resistance of a resistor. The resistors with more resistance will block large amount of electric current and allows very small amount of electric current. The resistors with less resistance will block very small amount of electric current and allows large amount of electric current. The electric current blocked by the resistor is wasted in the form of heat.
Resistors are the passive components. Hence, they cannot control the flow of electrons or electric current through them. However, they can restrict the electric current to certain level.
Units of resistor
The amount of electric current
blocked by the resistor is measured in ohms. The Ohm is often represented by the omega symbol: Ω.
Ohm is the amount of electric current blocked by
the resistor and allowed one ampere of electric current when an applied
voltage of one volt is kept constant.
We know that materials are mainly classified into two types: insulators and conductors
Insulators blocks large amount of electric current and allows very small amount of electric current whereas conductors allows large amount of electric current and blocks very small amount of electric current.
Resistors with more resistance act as insulators whereas the resistors with less resistance act as conductors.
The resistance of a resistor is directly proportional to the length of a resistor. The long length resistors offer high resistance because the free electrons have to travel large distance. Hence, a large number of free electrons collide with the atoms. Therefore, large amount of energy or electric current will be wasted in the form of heat.
The short length resistors offer low resistance because the free electrons have to travel only a short distance. Hence, a small number of free electrons collides the atoms. Therefore, only a small amount of electric current is wasted in the form of heat.
The resistance of a resistor is inversely proportional to the cross sectional area of resistor. The resistors with large cross sectional area provide more space for the free electrons to move freely. Hence, the collision of free electrons with the atoms is less. Therefore, very small amount of electric current is wasted.
The resistors with small cross sectional area provide very small space for the free electrons. Hence, the collision of free electrons with the atoms is more. Therefore, large amount of electric current is wasted.
Advantages of resistors
Resistors are very small. Hence, it is very easy to carry them from one place to another place.
Resistors are very cheap. Hence, it is easy to replace them.
Resistors do not depend on the external source of voltage. Hence, external voltage or energy is not needed for operating the resistors.
Disadvantages of resistors
Resistors with high resistance will oppose large amount of electric current. Hence, large amount of energy is wasted in the form of heat.
Answer the following questions
1 Was the text interesting for you? _______Y/ N
2 Was the text difficult for you? _________Y/N
3 How many new words have learnt from this text?
Color Code System
Resistors are the passive components used in the electrical circuits to reduce the flow of electric current to certain level. The ability to restrict the flow of electric current is called resistance. The resistors with high resistance value will restricts large amount of electric current whereas the resistors with low resistance value will restricts only a small amount of electric current. The resistance of a resistor is measured in Ohms (Ω), kilohms (1,000Ω=1kΩ) or Megohms (1,000,000Ω =1MΩ) Resistors can go in the circuit either way round.
The value is marked on the device with a colour code, or it can be measured with almost any multimeter. A
Generally, code refers to a representation of information in another form by using symbols, signals, and letters for the purposes of secrecy. Here, the signals or symbols act as codes. In the similar way, in resistors we use different colors as codes to specify the resistance (information) of the resistor. Here, the different colors coated on the resistor act as codes.
The color codes are used not only in resistors but also in other electronic components such as capacitors and inductors.
Specifying the values or ratings of electronic components such resistors, capacitors, and inductors by using the color codes printed on them is called electronic color code system. The electronic color code system was developed in the early 1920s by the radio manufactures association, which is now part of Electronic Industries Alliance (EIA).
The color-coding is done only in the fixed resistors but not in variable resistors because the color coding technique shows only a fixed resistance value. The variable resistors have varying resistance. Hence, it is not possible to use the color coding technique in variable resistors.
Printing the numbers on large electronic components is very easy, but it is very difficult to print the numbers or resistance values on tiny components. Hence, instead of directly printing the numbers, we print the color codes or color bands. However, by using the latest printing technology we can directly print the numbers on resistors.
The color coding technique has some drawbacks. For blind people, it is impossible to find the resistance of the resistor, because they cannot see the colors coated on the resistor.
Another drawback is recognizing the difference between two colors in an overheated resistor is very difficult. When the resistor is overheated, the colors on the resistor changes slightly. Therefore, it becomes impossible to recognize the difference between brown color and red color or brown color and orange color.
Answer the following questions
1 What is an electronic color code system?
2 When was it developed?
3 What are the disadvantages of the color code technique?
4 In what components are the color codes used?
5 Is it possible to use the color coding technique in variable resistors ?
Match the words in the right and left columns
1 hence a strip
2 reduce b covered
3 band c therefore
4 coated d drawback
5 disadvantage e decrease
Answer the following questions
1 Was the text interesting for yo ?_______Y/ N
2 Was the text difficult for you? _________Y/N
3 How many new words have learnt from this text?
Capacitors
Find the international words in the text
c …. , s …. , e …. , c …., s …. , c …. , d …. , c …. , m …. .
A capacitor
represents the amount of capacitance in a circuit. The capacitance is the
ability of a component to store an electrical charge. You can think of it as
the "capacity" to store a charge. The capacitance is defined by the
equation
C = q/V
where q is the charge in coulombs and V is the voltage.
Capacitance is measured in Farads. ), but one Farad is much too big to be practical.
Useful units are: Micro Farads (μF or uF) = 1/1,000,000th of a Farad , Nano Farads (nF) = 1/1,000,000,000th of a Farad , Pico Farads (pF) = 1/1,000,000,000,000th of a Farad
Capacitors less than 1uF can normally go in a circuit either way round. Larger capacitors normally have a polarity (normally the negative end is marked) and have to go in a circuit the right way round.
The symbol for
capacitance is two parallel lines. Sometimes one of the lines is curved as
shown below. The letter "C" is used in equations.
Capacitor Symbol
Capacitors store and release small amounts of electrical charge.
In electronic circuits they are used to control the timing of circuits, “smooth out” electrical waveforms and to separate DC and AC components of a signal. In a DC circuit, a capacitor becomes an open circuit blocking any DC current from passing the capacitor. Only AC current will pass through a capacitor.
Capacitors come in a many different types that are designed for different applications. For this circuit the type used isn't important so we've used the cheap and cheerful options. The small capacitors are “ceramic discs” and the large capacitors are “electrolytics”.
Several labelling schemes are in common use for capacitors. The ceramic discs used in these circuits are labelled with three digit codes. The first two digits are the value and the third digits is the number of zeros making up the capacitance in pF.
So: 10nF = 10,000 pF = “103” 100nF = 100,000pF = “104”
Michael Faraday
(22 September 1791 – 25 August 1867)
Discovered the fundamental relationship between electricity and magnetism (amongst many things).
Complete the sentences
1 Capacitors are used to …. DC and AC components of a signal.
2 Only …. current will pass through a capacitor.
3 The capacitance is ….. propotional to the voltage in the circuit.
4 Capacitors …. and …. small amounts of electrical charge.
5 The ability of a component to store an electrical charge is called ….. .
6 The small capacitors are labeled with …. digit codes.
7 The number of zeros making up the capacitance in pF is shown with the …. digit.
Answer the following questions
1. Was the text interesting for you ?_______Y/ N
2. Was the text difficult for you? _________Y/N
3. How many new words have learnt from this text?
Inductors
Find the international words in the text
i…. , c …. , r …., m …. , s ….. .
An inductor represents the amount of inductance in a circuit. The inductance is the ability of a component to generate electromotive force due to a change in the flow of current.
A simple inductor is made by looping a wire into a coil. When an electric current is passed through the coil, a magnetic field is formed around it. This magnetic field causes the inductor to resist changes in the amount of current passing through it.
An inductor's ability to store magnetic energy is measured by its inductance, in units of henries. The inductance of a coil is directly proportional to the number of turns in the coil. Inductance also varies with the coil's radius and the material (or "core") around which the coil is wound.
Inductors are used in electronic circuits to reduce or
oppose the change in electric current.
In a DC circuit, an inductor looks like a wire. It has no affect when the
current is constant. Inductance only has an effect when the current is changing
as in an AC circuit.
Inductance is measured in Henrys. The symbol for inductance is a series
of coils as shown below. The letter "L" is used in equations.
Inductor Symbol
Answer the following questions
1. What happens when an electric current passes through the wire coil?
2. How will the inductance of a coil change if we increase the number turns in the coil?
3. How is the ability of a
component to generate electromotive force due to a change in the
flow of current called ?
4. What do inductors do when the current in electronic circuit is constant?
Find the opposites in the text and complete the table
|
complex |
|
|
inversely proportional |
|
|
increase |
|
|
above |
|
|
inability |
|
Answer the questions
1 Was the text interesting for you ?_______Y/ N
2 Was the text difficult for you? _________Y/N
3 How many new words have learnt from this text?
Interesting Facts about Resistors, Capacitors, and Inductors
Test Quiz 1
Resistors, Capacitors, and Inductors
1. Which of the following
represents the ability of a component to store an electrical charge?
a. Resistance
b. Capacitance
c. Inductance
d. All of the above
e. None of the above
2. Which of the following represents the ability
of a component to generate electromotive force due to a change in the flow of
current?
a. Resistance
b. Capacitance
c. Inductance
d. All of the above
e. None of the above
3. Which of the following represents the ability
of a component to oppose the flow of current?
a. Resistance
b. Capacitance
c. Inductance
d. All of the above
e. None of the above
4. What is the standard unit of measurement for
resistance?
a. Volt
b. Henry
c. Farad
d. Ampere
e. Ohm
5. What is the standard unit of measurement for
capacitance?
a. Volt
b. Henry
c. Farad
d. Ampere
e. Ohm
6. What is the standard unit of measurement for
inductance?
a. Volt
b. Henry
c. Farad
d. Ampere
e. Ohm
7. What does the schematic symbol for a
capacitor look like?
a. A zigzag line
b. A series of coils
c. Two parallel lines
8. What does the schematic symbol for an
inductor look like?
a. A zigzag line
b. A series of coils
c. Two parallel lines
9. What does the schematic symbol for a resistor
look like?
a. A zigzag line
b. A series of coils
c. Two parallel lines
10. According to Ohm's Law, current equals the
voltage divided by the ……. .
a. Power
b. Inductance
c. Capacitance
d. Resistance
e. Conductance
Список использованной литературы
Electronics For Dummies 2010 John Wiley & Sons, Ltd
Интернет источники
http://www.newworldencyclopedia.org/entry/Inductor
Ответы
Test Quiz 1
1b, 2c, 3a, 4e, 5c, 6b, 7c, 8b, 9a, 10d
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