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CHAPTER 1: BJT AC ANALYSIS

(SMALL SIGNAL ANALYSIS)

COMMON EMITTER

CONFIGURATION

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BJT AC ANALYSIS

AC SMALL SIGNAL ANALYSIS-THISCHAPTER

AC LARGE SIGNAL ANALYSIS/POWERAMPLIFICATION-NEXT CHAPTER

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BASIC BJT AMPLIFIER

Tran!"#r !$%&' a a$%&!'!n *+,!+.

T+ #0"%0" !n0#!*a& !na& ! r+a"+r "an "+!n%0" # !n0#!*a& !na&.

T+ #0"%0" # AC %#+r ! r+a"+r "an AC !n%0". E!!+n' !n a$%&!!a"!#n 23P#(a)/P!(*)

S0%+r%#!"!#n "+#r+$ ! a%%&!a4&+ #r "+ana&'! # "+ 5C an* AC #$%#n+n" # a BJT

n+"#r67 %+r$!""!n "+ separation of theanalysis of the DC and AC response# "+'"+$

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AC SMALL SIGNAL ANALYSIS

S+""!n a&& 5C #0r+ "# 8+r# an*r+%&a!n "+$ 4' #r" !r0!"+90!,a&+n".

A&& a%a!"#r 4+#$+ #r"-!r0!".

R+arran+ !n !a& #r$.

E90!,a&+n" AC $#*+& :r+ $#*+&7'4r!* $#*+& an* '4r!* +90!,a&+n"$#*+&.

F!n* A$%&!'!n Ga!n.

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THE r+TRANSISTOR MO5EL(COMMON EMITTER )

E

e

I

mVr

26=

C

CE

o

IVr=

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PARAMETER IN AC SMALL SIGNALANALYSIS

r# : r#$ "+ ara"+r!"! 0r,+

ro

=

VCE

IC =

1

slope

VA

=ICQ

(VCEQ+VA)ICQ

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COMMON EMITTER ;OLTAGE-5I;I5ER BIAS

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5C E

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AC E

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AC E

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S"+% ?: E90!,a&+n" AC $#*+& :r+ $#*+&

AC E

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CASE 1: NO OUTPUT LOA5 @ NO AC ;OLTAGEAC ANALYSIS COMMON EMMITER WITH ;OLTAGE

5I;I5ER

R3R1R=

!3RDr+

In%0"I$%+*an+ :

O0"%0"I$%+*an+ :#3Rr

I r 1R# R

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;#3-(DIb)(Rr#)Ib3 ;!/Dr+;#3-D(;!/Dr+)(Rr#)Av=Vo/Vi=-(R!!ro)/re

;#&"a+ a!n:

Pa+ r+&a"!#n!%: N++"!,+ !n!n*!a"+ 1 %a+ !"4+"++n ;# an* ;!

CASE 1: NO OUTPUT LOA5 @ NO AC ;OLTAGEAC ANALYSIS COMMON EMMITER WITH ;OLTAGE

5I;I5ER

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;#3-(DIb)(R//RL)Ib3 ;!/Dr+;#3-D(;!/Dr+)(R//RL)Av"=Vo/Vi=-(R//R")/ re

;#&"a+ a!n !" a*: RL3r//R//RLR//

RL

CASE =: OUTPUT LOA5 @ NO AC ;OLTAGEAC ANALYSIS COMMON EMMITER WITH ;OLTAGE

5I;I5ER

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!3R1R=Dr+#3Rr#

Av"=Vo/Vi=-(R//R")/ re

;#&"a+ a!n !" AC!n%0":

A,3(!/

(!R))A;L

CASE =: OUTPUT LOA5 @ AC ;OLTAGEAC ANALYSIS COMMON EMMITER WITH ;OLTAGE

5I;I5ER

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AC ANALYSIS COMMON EMMITER

WITH ;OLTAGEEK+r!+