Task 7. Read the Text. The clockwork radio

Trevor Baylis is an inventor. In 1991, he heard about the problem of bringing health information to people in rural Africa. Radio was the best way but people had no electricity and couldn't pay for expensive batteries. So he invented a radio which doesn't need mains power or batteries. Instead, it consists of a spring, gears, and a small generator.

So how does his clockwork radio actually function? As you turn the handle on the side of the radio, you wind up a spring. It's the same kind of steel spring used in car safety belts. It takes 60 turns to wind up the spring fully.

When the spring starts to unwind, the gears engage. There are three 1:10 step-up gears. The last step-up link is a pulley. Pulleys run more quietly than gears so this reduces noise. Each time the first gear turns, the generator turns one thousand times. As it turns, it generates electricity - a voltage of 3 V at about 30 mA. The spring has enough power to run the radio for 30 minutes before you have to wind it up again.

More than two million clockwork radios are in use all over the world. Trevor Baylis has also invented an 'electric shoe'. It charges batteries as you walk.

Методические рекомендации:

Для полного понимания текста следует просмотреть активную лексику, и если необходимо, обратиться к англо-русскому словарю. Затем провести аудиторную работу над текстом с аналитическим чтением, контролем понимания и закреплением с помощью упражнений.

Рекомендуемая литература:

осн.(стр. 48-50),9 осн.(стр 202-213)

Контрольные вопросы:

1. How is the telephone conversation carried on?

2. What is the number of long distance calls per year by statistics reports?

3.Are there any disadvantages of space satellites.

4. Which device produces high-frequency energy?

5. Is a microphone connected to the circuit of the transmitting antenna?

6. What necessary components of a radio do you know?

7. What means is the antenna grounded by?

8. What means is the transmitted sound reproduced by?

9. What kind of current produces oscillations?

10. Which device receives radio waves?

Дата добавления: 2015-11-14