Exercise 9. Fill in the blanks with the words or word-combination from the list below
1. Making use of the … in different fields plays an unprecedented role in progress and science.
2. A potentiometer acts as a … or rheostat when two terminals (one end and the wiper) are used.
3. A measuring instrument is a device for measuring a ...
4. When overloaded the ammeter and voltmeter are both … to overheating.
5. If … during a day are desired, meters may measure the use of power in some interval.
6. The process of … gives a number relating the item under the study and the referenced unit of measurement.
(energy savings, latest technology, physical quantity, variable resistor, measurement, vulnerable
Exercise 10. Match the words in column I with their definitions in column II
| I | II |
| 1.A multimeter is a measuring device | a) to measure the amount of consumed electric energy |
| 2. An ammeter is a measuring device | b) used for utility frequency and audio frequency power measurements. |
| 3. An electromagnetic wattmeter is a device | c) to measure electric potential (voltage) |
| 4. An energy meter is a measuring device | d) to measure the current in a circuit |
| 5. A potentiometer is a voltage divider used | e) to measure voltage, current and resistance |
Exercise 11. List the most important measuring devices in your field of engineering and explain your choice.
Exercise 12. State the main idea of the text
Exercise13. Render the text into English
Средства электрических измерений широко применяются в энергетике, связи, промышленности, на транспорте, в научных исследованиях, в медицине и быту для учета потребляемой энергии.
Главным признаком для классификации электроизмерительной аппаратуры является измеряемая физическая величина. В этой связи приборы предназначены для измерения силы электрического тока (амперметры), электрического напряжения (вольтметры), электрического сопротивления (омметры), частоты колебаний электрического тока (частотомеры - frequency counter), мощности электрического тока, потребления электроэнергии и др.
|
|
|
По принципу действия приборы делятся на электромеханические, магнитоэлектрические, электромагнитные, электродинамические, электростатические, индукционные, электронные, термоэлектрические и т.д.
Self-Study Section
Exercise 14.Read the text B
1. Any instrument which measures electrical values is called a meter. A meter measures the current in amperes. The unit is named after Andre Marie Ampere, a French scientist, who discovered a great number of facts about electricity over a hundred years ago. The abbreviation for the ampere is amp. A voltmeter measures the voltage and the potential difference in volts. The volt is named after Alessandro Volta, an Italian scientist.
2. The current in a conductor is determined by two things, the voltage across the conductor and the resistance of the conductor. Every material offers some resistance to the flow of an electric current through it. Good conductors like metals (copper, silver and aluminium) offer very little resistance, while nonconductors such as glass, wood, and paper offer a very high resistance.
3. The unit by which resistance is measured is called the ohm. The resistance in practice is measured with ohmmeter. A wattmeter measures electrical power in watts. Very delicate ammeters are often used for measuring very small currents. A meter whose scale is calibrated to read a thousandth of an ampere is called a milliammeter. One whose scale is calibrated in millionth of an ampere is called a microammeter or galvanometer.
4. Whenever an ammeter or voltmeter is connected to a circuit to measure electric current or potential difference the ammeter must be connected in series and the voltmeter in parallel.
Exercise 15. Choose the best title to the text
a). Electric measuring units and instruments
b). Electric measuring instruments
c). Electric measuring units
Exercise 16. Put sentences in proper order according to the text
|
|
|
a). An ammeter is an instrument measuring the value of the electric current.
b). A voltmeter measures the potential difference.
c). An ammeter and a voltmeter are connected to the electric circuit differently .
d) Resistance is measured in ohms and power in watts.
Дата добавления: 2019-02-22; просмотров: 345; Мы поможем в написании вашей работы! |
Мы поможем в написании ваших работ!