2.9 Part 9

1. Remember pronunciation of the following words

emphasize, influence, bias, depletion, carrier, diffusion, forward, therefore, roughly, right, capture.

2. Read the words, pay attention to stress shift

local — locality; filament — filamentary; act — activity; operate — operation; sensitive — sensitivity.

3. Find Russian equivalents to the English words

conductance

filamentary transistor

reverse biased /p-n junction

blocking effect

depletion

diffusion tails

injection

minority carriers

reverse current

forward biased point contact

forward direction смещенный точечный контакт диффузные шлейфы неосновные носители истощение инжекция

прямое направление обратный ток проводимость нитевидный транзистор обратно-смещенный р-п переход блокирующий эффект

2.9.4 Find synonyms, translate them

ordinary <2, differ v, complicated a, application is made, chiefly adv, vary v, precision n, use is made, conventional a, accuracy mainly adv, complex <2.

5. Find antonyms, translate them

act v, seldom adv, input current, sophisticated <2, transmit v, result from v, minority carriers, reduce v, counteract v, result in v, frequently adv, output current, raise v, re­ceive v, majority carriers, simple a.

5. Analyse these sentences before translating: divide nominative and verb word-combinations. Find predicates and subjects, identify their grammatical features

1. This results in voltage and power amplification without current amplification. 2. Current amplification is possible only if, the space charge action of the minority carriers, requiring a concentration increase of the majority carriers, comes into play.

5. Read the questions before reading the text, find the answers in the

text

1. What is a common principle of the mechanism of some transistor types? 2. What is the cause of blocking? 3. What is essential for the functioning of the n-p-n transistor?

THE N-P-N TRANSISTORS

We have emphasized in the introduction, as a common principle of the mechanism of some transistor types, that the conductance of a current path containing a strong "local" current source is influenced by the small controlling power of a current coming from "far away". In the filamentary, transistor the influenced current path is a piece of ohmic conductor, whereas in the n-p-n transistor it is a reverse-biased p-n junction(see Figure 10.). The in the cause of the blocking effect of such a p-n junction is the depletion of minority carriers diffusion tails, which ordinarily act as current sources. Counteracting this carrier depletion by the injection of a varying number of minority carriers results in a control action on the reverse current of the junction. The injector or emitter in an n-p-n transistor is not a forward-biased point contact but another p-n junction which is biased in the forward direction, in contrast to the collector. Thus we arrive at the n-p-n transistor shown in Figure 10, as the final stage. The operation of this transistor type is, therefore, based roughly on the following mechanisms: the left n-p junction, which is biased in the forward direction emits electrons into the central p-layer; these electrons are collected by the p-n junction on the right which is biased in the reverse direction, and the reverse resistance of this p-n junction acting as collector is a sensitive function of the number of captured electrons. The electron currents flowing in the n-p-n transistor are therefore essential for its functioning.

Notes to the text

forward biased point contact — смещенный точечный контакт forward direction — прямое направление

ь. p^ Emitter ПТп Base U [J Collector

|[le

ь

Emitter

reverse-biased p-n junction — обратно-смещенный p-n переход

lb	1	Ic
	J

lb

Base

Ic

Collctor

nip Emitter J—, Junctions

Junctions

H ^

|l I Collei ^Base ll lb

Base

Figure 10-The Transformation of the Filamentary Transistor into the n-p-n Transistor

2.9.8 Translate the word-combinations

current amplification, captured electrons, forward biased, reverse biased, current path, controlling power, filamentary transistor, ohmic conductor, blocking effect, diffusion tails, reverse current, forward biased point contact transistor.

9. Answer the questions

1. What is the conductance of a current path containing a- strong local current source influenced by? 2. What is the influenced current path in the filamentary transistor and the n-p-n transistor? 3. What is the cause of the blocking effect of a p-n junction? 4. What is the injector or emitter in an n-p-n transistor? 5. What is the operation of this transistor type based on?

9. Define parts of speech. Underline suffixes and, translate the words

conductance, ohmic, conductor, depletion, minority, ordinarily, emitter, final, roughly, layer, sensitive.

9. Read and translate without a dictionary

ABOUT THE SO-CALLED P-N JUNCTION

Our ideas about the structure and mechanism of commercial crystal rectifiers have changed during recent years. The introduction of a radically new type of rectifier is partially responsible for this change. This is the so-called p-n junction. It was developed by W. Shockley but as early as 1938 B. Da-vydov pointed out that strong unipolar effects are to be expected at the junction between p-type and n-type semiconductors.