전자회로I

다섯째주 1강

Chapter 3

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2016년 6월 27일2 pages

Operation of the npn Transistor in the Active mode The collector Current

we can express the collector current iC as

(5.3) / TBE VvSC eIi

The saturation current Is is given by

WnqDAI pnES /0

Substituting nP0 = ni2/NA, where ni is the intrinsic carrier density and NA

is the doping concentration in the base, we can express IS as

(5.4) 2

WNnqDAI

A

inES

Chapter 3

Lecture Homepage : http://signal.korea.ac.kr

2016년 6월 27일3 pages

Operation of the npn Transistor in the Active mode The Base Current

(5.5) /2

1TBE Vv

pD

ipEB e

LNnqDA

i

The base current iB is composed of two components

(5.6) 2b

nB

Qi

Chapter 3

Lecture Homepage : http://signal.korea.ac.kr

2016년 6월 27일4 pages

Operation of the npn Transistor in the Active mode The Base Current

WnqAQ pEn )0(21

Substituting for np(0) from Eq. (5.1) and replacing np0 by ni2/NA gives

(5.7) 2

/2

TBE Vv

A

iEn e

NqWnAQ

which can be substituted in Eq. (5.6) to obtain

(5.8) 21 /

2

2TBE Vv

Ab

iEB e

NqWnAi

Combining Eqs. (5.5) and (5.8) and utilizing Eq. (5.4), we obtain for thetotal base current iB the expression

(5.9) e W21 TBE/Vv

2

bnpD

A

n

pSB DL

WNN

DD

Ii

Chapter 3

Lecture Homepage : http://signal.korea.ac.kr

2016년 6월 27일5 pages

Operation of the npn Transistor in the Active mode The Base Current

Comparing Eqs. (5.3) and (5.9), we see that iB can be expressed as afraction of iC as follows :

(5.10) C

Bii

(5.11) TBE /VvSB eIi

(5.12) 21/1

2

bpD

A

n

p WLW

NN

DD

Chapter 3

Lecture Homepage : http://signal.korea.ac.kr

2016년 6월 27일6 pages

Operation of the npn Transistor in the Active mode The Emitter Current

(5.19) 1

(5.18) )/(

(5.17) 1

(5.16)

)15.5(1

(5.14) 1(5.13)

/

/

TBE

TBE

VvSE

EC

VvSE

CE

BCE

eIi

ii

eIi

ii

iii

Chapter 3

Lecture Homepage : http://signal.korea.ac.kr

2016년 6월 27일7 pages

Equivalent-Circuit Models

Chapter 3

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2016년 6월 27일8 pages

Structure of Actual Transistors

Chapter 3

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2016년 6월 27일9 pages

Minority Carrier Concentration in Saturation Mode

Chapter 3

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2016년 6월 27일10 pages

The pnp Transistor

Chapter 3

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2016년 6월 27일11 pages

Equivalent Circuit Model: PNP Transistor

Chapter 3

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2016년 6월 27일12 pages

Circuit Symbols and Conventions

Chapter 3

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2016년 6월 27일13 pages

Current-Voltage CharacteristicsGraphical Representation of Transistor Characteristics

/ VBE TC Si I e

Chapter 3

Lecture Homepage : http://signal.korea.ac.kr

2016년 6월 27일14 pages

Current-Voltage CharacteristicsGraphical Representation of Transistor Characteristics