Choose the appropriate English equivalents
1. ближе— 1. close; 2. closer; 3.the closest
2. лучше— 1. good; 2. better; 3. the best
3. больше— 1. the most; 2. more; 3. Much
4. самый маленький— 1.small; 2. smaller; 3. the smallest
5. самый большой— 1. the largest; 2. large; 3. larger
6. выше—1. high; 2. higher; 3. the highest
Remember the spelling: big – bigger
Translate the following sentences. Mind the meaning of the highlighted words.
1. The farther the grid is from the cathode, the more the plate current is. 2. The wider the distance between the grid wires, the more the plate current is. 3. The higher the temperature, the lower the conductivity of a metallic conductor. 4. The lower the temperature, the better the conductivity of a metallic conductor.
5. The slower the electrons move, the easier it is to stop them and return them to the space charge. 6. The closer the grid is to the cathode, the more control it will have on electron flow to the plate. 7. The more heavily the material is doped, the lower its electrical resistance will be. 8. The hotter the cathode becomes, the more electrons it emits per unit time (в единицу времени). 9. As the electrons move out into space, they form a cloud (облако) of negative charges. The larger this cloud becomes, the more opposition it offers to additional electrons leaving the cathode. 10. The more negative the grid, the less the plate current will be. 9. The greater the load resistance of a tube amplifier, the greater is the voltage amplification.
10. Translate
A. Start from the first component:
anode current; electron tube; large plate current; semicoductor device; small negative voltage; large negative voltage; gas-filled envelope
B. Start from the second component:
electron flow; current flow; potential increase
Translate the following sentences. Start your translation from an adverbial modifier of place.
1. There is one grid in a triode. 2. There are two grids in a tetrode. 3. There are three grids in a pentode. 4. There is no grid in a diode.
Match the following sentences with their translations
| 1. The third element is called "a grid". | A. Чем ближе сетка к катоду, тем больше у нее влияние на поток электронов. |
| 2. It is placed between the cathode and the plate. | B. К сетке приложено низкое отрицательное напряжение. |
| 3. The purpose of a grid is to control the flow of electrons. | C. Это приводит к возникновению большого анодного тока. |
| 4. The closer the grid is to the cathode, the more influence it has on the electron flow. | D. Вакуумные триоды могут усиливать ток. |
| 5. The more negative the grid, the less the plate current. | E. Третий элемент называется «сеткой». |
| 6. A small negative voltage is applied to the grid. | F. Она помещается между катодом и анодом. |
| 7. This results in a large plate current. | G. Назначение сетки - управлять потоком электронов. |
| 8. Vacuum triodes can amplify current. | H. Чем более отрицательна сетка, тем меньше будет анодный ток. |
|
|
|
Choose as many words from the table о f ex. 1 as you can and form sensible sentences in Present Continuous (affirmative, negative and interrogative).
For example: In fig. A the grid is controlling the current flow.
Specialist Reading
Read the text “ Triodes ” and choose its best summary.
1. The electron flow in a triode.
2. The influence of the grid on the electron flow.
3. The structure of a triode, basic principles of its operation and functions.
In a vacuum-tube triode there are three electrodes: a cathode, a plate and a grid. When heated the cathode emits electrons. Electrons flow from the cathode to the plate. The grid is placed between the cathode and the plate. It controls the flow of electrons. The closer the grid is to the cathode, the more influence it has on the electron flow. Even if a small negative voltage is applied to the grid, this results in a large plate current. If a large negative voltage is applied to the grid, the plate current decreases. For example, the plate voltage is 150 volts. A small negative voltage of 10 volts is applied to the grid. This results in a current flow of 20 m. a. But if the negative voltage on the grid is decreased to 8 volts, this will result in a current of 30 m.a. Due to this property of a triode, it can be used for amplification.
|
|
|
Дата добавления: 2022-11-11; просмотров: 14; Мы поможем в написании вашей работы! |
Мы поможем в написании ваших работ!