Input & Output Characteristics
COMMON BASE (CB)
Engr.Usman Ali Khan
CONTENTS
1. CB, CE and CC
2. CB Circuit
3. CB Input Characteristics
4. CB Output Characteristics
BJT CONFIGURATIONS• Common Base (CB)
• Common Emitter (CE)
• Common Collector (CC)
COMMON BASE (CB)
Input Output
B
E C
Base is common both to input signal and output signal
COMMON EMITTER (CE)
Emitter is common both to input signal and output signal
Input
Output
E
C
B
COMMON COLLECTOR (CC)
Collector is common both to input signal and output signal
Input
Output
E
C
B
CB VOLTAGES AND CURRENTS
E
C
B
E
C
B
NPN PNP
IB
IE
IC
IB
IE
IC
VBE = 0.7 VEB = 0.7
VBE = -VEB
CB INPUT CHARACTERISTICS
B
E C
VBE
IE
VBC
IC
Input SideOutput Side
To observe the behavior of Base-Emitter junction when VBC is fixed
CB INPUT CHARACTERISTICS
VBE
IE
VCB = 0VVCB = 10V
VCB = 25V
0.7
CB OUTPUT CHARACTERISTICS
B
E C
VBE
IE
VBC
IC
Input SideOutput Side
To observe the behavior of Base-Collector junction when IE is fixed
CB OUTPUT CHARACTERISTICS
VBC
IC
-1 0 5 10
IE = 1mA
IE = 2mA
IE = 3mA
IE = 4mA
Saturation Region
Active Region
Junction Forward Biased Junction
Reverse Biased
Break down Region or Punch Through Region (Depletion Regions Overlap)
HOME WORK• Example: 4.2, 4.3
• End Problems: 4.6 4.7
Input & Output Characteristics
COMMON EMITTER (CE)
CONTENTS
1. β
2. CE Configuration
3. CE Input Characteristics
4. CE Output Characteristics
CE CONFIGURATION
InputE
C
B
Output
VCE
VCB
VBE
IB
IE
ICIE = IC + IB
VCE = VCB + VBE
VCE = VCB + 0.7
Input Current = IB
Input Voltage = VBE
Output Current = IC
Output Voltage = VCE
B
C
BC
CBOBC
CBOBC
CBOBC
BCECBOC
ECBOC
CBOEC
EINJC
CBOINJCC
I
I
II
III
III
III
IIIII
III
III
II
III
1
11
1
1
1
11
)(
)(
IC = 1mAIB = 10 µAβ =?
CE INPUT CHARACTERISTICS
VBE
IB
VCE = 20V
VCE = 10V
0.7
CE OUTPUT CHARACTERISTICS
VCE
IC
5 10 15 20
IB = 10 µA
IB = 20 µ A
IB = 30 µ A
IB = 40 µ A
Saturation Region
Active Region
Junction Reverse Biased
Break down Region or Punch Through Region (Depletion Regions Overlap)
HOME WORK• CC Characteristics
• Example: 4.4 4.6
• End Problems: 4.8 4.17
HOME TASK
• Make CC(Common Collector) Configuration and draw input output characteristics…