Unit 12

Task 1. Match the words and phrases with the translations.

1.	amplifier		a	доставлять
2.	respond to		b	характеристика
3.	input signal		c	твердотельная микросхема
4.	deliver		d	удовлетворительный
5.	output signal		e	употреблять, применять
6.	waveform		f	общий
7.	feature		g	вовлекать, включать в себя
8.	receiver		h	реагировать
9.	high-fidelity		i	подавать (питание), передавать
10.	employ		j	этап
11.	solid-state microcircuit		k	приемник
12.	raise		l	соединение (в пару)
13.	level		m	усилитель
14.	feed into		n	многоступенчатый
15.	satisfactory		o	усиление
16.	multistage		p	форма сигнала (волны)
17.	overall		q	увеличивать
18.	gain		r	входной сигнал
19.	coupling		s	поднимать, увеличивать
20.	involve		t	высокоточный
21.	successive		u	помехи
22.	stage		v	последовательный
23.	magnify		w	выходной сигнал
24.	distortion		x	уровень

TASK 2. Read the text about amplifiers and complete it with the words and phrases.

output signal, amplifier, receivers, responds to, high-fidelity, input signal, delivers, waveform, employ

1. … is a device that 2) … a small input signal (voltage, current, or power) and 3) … a larger 4) … that contains the essential 5) … features of the 6) … . Amplifiers of various types are widely used in such electronic equipment as radio and television 7) …, 8) … audio equipment, and computers. Amplifying action can be provided by electromechanical devices (e.g., transformers and generators) and vacuum tubes, but most electronic systems now 9) … solid-state microcircuits as amplifiers. Such an integrated circuit consists of many thousands of transistors and related devices on a single tiny silicon chip.

multistage, gains, to raise, overall, satisfactory, level, fed into

A single amplifier is usually not enough 10) … the output to the desired 11) …. In such cases the output of the first amplifier is 12) … a second, whose output is fed to a third, and so on, until the output level is 13) …. The result is cascade, or 14) … amplification. Long-distance telephone, radio, television, electronic control and measuring instruments, radar, and countless other devices all depend on this basic process of amplification. The 15) … amplification of a multistage amplifier is the product of the 16) … of the individual stages.

successive, coupling, solid-state, involved, stages

There are various schemes for the 17) … of cascading electronic amplifiers, depending upon the nature of the signal 18) … in the amplification process. 19) … microcircuits are better than vacuum-tube circuits for the direct coupling of 20) … amplifier 21) … . Transformers can be used for coupling, but they are too big and expensive.

distortion, magnified

An electronic amplifier can be designed to produce a 22) … output signal identical in every respect to the input signal. This is linear operation. If the output is altered in shape after passing through the amplifier, amplitude 23) … exists. If the amplifier does not amplify equally at all frequencies, the result is called frequency distortion, or discrimination.

task 3. Answer the questions below and retell the text.

1. What is the main purpose of the amplifier? 2. Where are amplifiers used? 3. What electromechanical devices are used to provide the amplification of the input signals? 4. What can be done in case if the single amplifier is not enough to get a desired level of signal? 5. What are the examples of devices which depend on the multistage amplification? 6. What is the overall amplification of the multistage amplifier due to? 7. Why are microcircuits better for coupling than transformers? 8. What causes amplitude distortion?

TASK 4. Match the names with the descriptions.

Current amplifier

Transresistance amplifier