BJT Topologies – Basic Bias · 2017-05-31 · forward bias reverse bias forward bias reverse...
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Young Won Lim 05/31/2017 BJT Topologies – Basic Bias
Transcript of BJT Topologies – Basic Bias · 2017-05-31 · forward bias reverse bias forward bias reverse...
Young Won Lim05/31/2017
BJT Topologies – Basic Bias
Young Won Lim05/31/2017
Copyright (c) 2012 – 2017 Young W. Lim.
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BJT Topologies – Basic Bias
3 Young Won Lim05/31/2017
BJT Amplifier Topologies
n p nE
B
C
Common Base
n p n
B
Common Base
E
B
C
Common Emitter
n
p
n
E
BC
Common Emitter
n
p
n
E
B
C
Common Collector
n
p
n
E
B
C
Common Collector
n
p
n
E C
BJT Topologies – Basic Bias
4 Young Won Lim05/31/2017
Common Base Topology
n p n
E
B
C
Current Flow
Common Base
n p n
E C
B
Current Flow
Common Base
IN OUT IN OUT
BJT Topologies – Basic Bias
5 Young Won Lim05/31/2017
Common Emitter Topology
E
B
C
Current Flow
Common Emitter
n
p
n E
B
C
Current Flow
Common Emitter
n
p
n
IN
OUT
IN
OUT
BJT Topologies – Basic Bias
6 Young Won Lim05/31/2017
Common Collector Topology
E
B
C
Current Flow
Common Collector
n
p
n
E
B
C
Current Flow
Common Collector
n
p
n
IN
OUT
IN
OUT
BJT Topologies – Basic Bias
7 Young Won Lim05/31/2017
Forward bias (BE) & Reverse bias (CB)
E
B
C E
B
C
n
p
n
n
p
n
Common CollectorCommon EmitterCommon Base
n p n
E C
B
n
p
n
E
B
C
n
p
n
E
B
C
V BE
V CB
forward biasreverse bias
V BE
V CB
forward biasreverse bias
V BE
V CB
forward biasreverse bias
n p n
B
E C
BJT Topologies – Basic Bias
8 Young Won Lim05/31/2017
Biasing Back-to-back Diodes
Common CollectorCommon EmitterCommon Base
n p n
E C
B
n
p
n
E
B
C
n
p
n
E
B
C
V BE
V CB
forward biasreverse bias
V BE
V CB
forward biasreverse bias
V BE
V CB
forward biasreverse bias
++ – –
+
+–
–
+
+–
–
BJT Topologies – Basic Bias
9 Young Won Lim05/31/2017
Two voltage supplies
E
B
C E
B
C
n
p
n
n
p
n
Common CollectorCommon EmitterCommon Base
V BE
V CB
forward biasreverse bias
V BE
V CB
forward biasreverse bias
V BE
V CB
forward biasreverse bias
V BE V CB V BE V CE V CB V CE
n p n
B
E C
BJT Topologies – Basic Bias
10 Young Won Lim05/31/2017
Two voltage supplies controls VBE & VCB
E
B
C E
B
C
n
p
n
n
p
n
Common CollectorCommon EmitterCommon Base
V BE
V CB
V BE
V CE
V CB
V CE
n p n
B
E C
Voltage of B from E
Voltage of C from B
Voltage of B from E
Voltage of C from E
Voltage of C from B
Voltage of C from E
V CB + V BE V CB + V BE
+
–
–
+
–
+
–
+
–
+
–
+
BJT Topologies – Basic Bias
11 Young Won Lim05/31/2017
Two voltage supplies with resistors
n p n
B E
B
C E
B
C
n
p
n
n
p
n
++
+
+
+
+
– –
–
–
– –
Common CollectorCommon EmitterCommon Base
V BE V CB
V BE V CE V CB V CE
n p n
n
p
n
n
p
n
E C
V CB V BE
E B C
C
B
E
E
B
C
BJT Topologies – Basic Bias
12 Young Won Lim05/31/2017
BJT Topologies – Basic Bias
13 Young Won Lim05/31/2017
Common Base (1)
n p n
E
B
C
Common Base
n p n
E
B
C
Electron Flow Current Flow
Common Base
forward bias reverse bias forward bias reverse bias
BJT Topologies – Basic Bias
14 Young Won Lim05/31/2017
Common Base (2)
n p n
E
B
C
Electron Flow
n p n
E C
n p n n p n
B
E
B
C E C
B
Current Flow
Common Base Common Base
BJT Topologies – Basic Bias
15 Young Won Lim05/31/2017
Common Emitter (1)
E
B
C
E
B
C
Electron Flow Current Flow
Common Emitter Common Emitter
n
p
n
n
p
nforward bias
reverse bias
forward bias
reverse bias
BJT Topologies – Basic Bias
16 Young Won Lim05/31/2017
Common Emitter (2)
E
B
C
E
B
C
Electron Flow Current Flow
Common Emitter Common Emitter
n
p
n
n
p
n
n
p
n
n
p
n
BJT Topologies – Basic Bias
17 Young Won Lim05/31/2017
Common Collector (1)
E
B
C
E
B
C
Electron Flow Current Flow
Common Collector Common Collector
n
p
n
n
p
n
forward bias
reverse bias
forward bias
reverse bias
BJT Topologies – Basic Bias
18 Young Won Lim05/31/2017
Common Collector (2)
E
B
C
E
B
C
Electron Flow Current Flow
Common Collector Common Collector
n
p
n
n
p
n
n
p
n
n
p
n
BJT Topologies – Basic Bias
19 Young Won Lim05/31/2017
BJT Bias
n p nE C
n p n
B E
B
C E
B
C
n
p
n
n
p
n
n
p
n
n
p
n
E
B
C E
B
C
E C
B
++
+
+
+
+
– –
–
–
– –
Common CollectorCommon EmitterCommon Base
V BE V CB
V BE V CE V CB V CE
BJT Topologies – Basic Bias
20 Young Won Lim05/31/2017
Common Emitter (2)
Electron Flow
n p n
E C
Current Flow
n p n n p n
B
BJT Topologies – Basic Bias
21 Young Won Lim05/31/2017
Maintain Magnetic Field
Before Initial Final
No Energy in magnetic field
+
−
Induced EMF
Young Won Lim05/31/2017
References
[1] http://en.wikipedia.org/[2] J.H. McClellan, et al., Signal Processing First, Pearson Prentice Hall, 2003
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