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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!+