Lecture 06
Single Stage Analysis
Content
common-emitter stage (CE)
excel programming
common-collector stage (CC)
multistage analysis
Electrical & Computer Engineering
King Abdulaziz University
Slide 2
Solve This Amplifier
Electrical & Computer Engineering
King Abdulaziz University
Slide 3
Solve This Amplifier
(
)
= Rq 2 // 0.882 × 101 + 0.147
= 0.05 × 101 + 0.218
= (30 // 1) × 101 + 0.147
io
1
=
i6
1 + 30
0.991
i5
=
i 4 0.991 + Rq 1
0.882
i3
=
i2 0.882 + Rq 2
i6
= 101
i5
i4
= −100
i3
i2
= 101
i1
Electrical & Computer Engineering
King Abdulaziz University
100
i1
=
is 100 + Rq 3
Slide 4
session 01
Common-Emitter (CE)
DC Analysis
VBB
R2
= VCC
R1 + R2
RB
= R1 // R2
IB
=
rπ
Electrical & Computer Engineering
King Abdulaziz University
VBB − 0.7
RB + (β + 1) ⋅ RE
VT
=
IB
Slide 6
Common-Emitter (CE)
AC Analysis
Electrical & Computer Engineering
King Abdulaziz University
RXX
= rπ + (β + 1) ⋅ RX
Ri
= RB // RXX
ro
= RC
AV 0
RC
= −β
RXX
Slide 7
CE Equivalent Network
Electrical & Computer Engineering
King Abdulaziz University
Slide 8
Equivalent Circuit
 Ri 
 RL 
AVT = 
 ⋅ AV 0 ⋅ 
 = ki ⋅ AV 0 ⋅ ko
 Ri + RS 
 RL + ro 
Ri
ki =
Ri + RS
Electrical & Computer Engineering
King Abdulaziz University
RL
ko =
RL + ro
Slide 9
CE Limits and Conditions
internal gain limits:
RC
1 < AV 0 ≤ β
rπ
input resistance limits:
rπ ≤ Ri < RB
input source limits:
VC
= VCC − I C RC
VB
= VBB − I B RB
Electrical & Computer Engineering
I B RXX
−
≤ vS
ki
King Abdulaziz University
VC − VB
≤
ki + AVT
Slide 10
session 02
Excel Analysis
Electrical & Computer Engineering
King Abdulaziz University
Slide 12
session 03
Example
Electrical & Computer Engineering
King Abdulaziz University
Slide 14
Solution DC Analysis
VBB
R2
= VCC
R1 + R 2
= 10 V
RB
= R1 // R2
= 24kΩ
IB
rπ
Electrical & Computer Engineering
VBB − 0.7
=
RB + (β + 1) ⋅ RE
VT
=
IB
King Abdulaziz University
= 37.13µA
= 673Ω
Slide 15
Solution AC Analysis
RXX
= rπ + (β + 1) ⋅ RX
= 15.8kΩ
Ri
= RB // RXX
= 9.5kΩ
ro
= RC
= 1.5kΩ
AV 0
RC
= −β
RXX
= 14.3
ki
ko
AVT
Electrical & Computer Engineering
King Abdulaziz University
Ri
=
Ri + RS
RL
=
RL + ro
= 0.67
= ki ⋅ AV 0 ⋅ k o
= 10.09
= 0.93
Slide 16
Input Range
VC
= VCC − IC RC
= 16.65V
VB
= VBB − I B RB
= 9.11V
Electrical & Computer Engineering
I B RXX
−
ki
≤ vS
VC − VB
≤
ki + AVT
− 0.8
≤ vS
≤ +0.7
King Abdulaziz University
Slide 17
session 04
Common-Collector (CC)
DC Analysis
IB
rπ
Electrical & Computer Engineering
King Abdulaziz University
VCC − 0.7
RB + (β + 1) ⋅ RE
VT
=
IB
=
Slide 19
Common-Collector (CC)
AC Analysis
RXX = rπ + (β + 1) ⋅ REL
Ri
Ro
AV 0
Z
= RB // RXX
 r + RSB 

= RE // π
 β +1 
(β + 1) ⋅ RE
=
rπ + (β + 1) ⋅ RE
≈ β ⋅ RL
≈
RS
β
≈1
= (RB + RXX )RS + RB RXX
I Z
I Z
− B ≤ vS ≤ B
RB
RXX
Electrical & Computer Engineering
King Abdulaziz University
Slide 20
CC Equivalent Network
Ri (RL → ∞ )
Electrical & Computer Engineering
King Abdulaziz University
Slide 21
Multistage Analysis
CC
Electrical & Computer Engineering
CE
King Abdulaziz University
CC
Slide 22
Example
Electrical & Computer Engineering
King Abdulaziz University
Slide 23