analysis of ce amplifier
TRANSCRIPT
Analysis of CE Amplifier
Yong Heui Cho @ Mokwon University
Some of slides are referred to:[1] A. S. Sedra & K. C. Smith, Microelectronic Circuits.
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Electronic Circuits
9. BJT – Model
10. BJT – Analysis of Bias
11. Analysis of CE Amplifier
12. BJT – Advanced Applica-tions
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CE Amplifier• CE (Common Emitter)• Input: Base, Output: Collector• Common: Emitter
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Active Condition• Collector Current (IC) = about mA• CE Voltage (VCE) = VCC/2
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Bias Point
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Transconductance
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Input Resistance
Small signal Emitter resistance : re
Voltage Gain
vc = -icRC = gmvbeRC = (-gmvbe)RC Av = vc/vbe = -gmRC = -ICRC/VT
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Hybrid p Model
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High Frequency Model
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Final CE Amplifier
RB1
RB2 CE
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Capacitor• DC – open• AC – almost short
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Equivalent Circuit• DC voltage → short
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2111 //
BB
BBBBB RR
RRRRR
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Voltage Gain
in//// v
rRRrRvBS
B
p
pp
in
out
//)//)(//(
)//()//(
vrRRrRRRg
vRRgRRiv
BS
BLCm
LCmLCc
p
p
p
p
p
rRRrRRRg
vvA
BS
BLCmV //
)//)(//(
in
out
p
rRRR
vvA
S
LCV
)//(
in
out
ro: almost open