Download Common-emitter circuit

EKT104 ANALOG
ELECTRONIC CIRCUITS
[LITAR ELEKTRONIK ANALOG]
DR NIK ADILAH HANIN BINTI ZAHRI
[email protected]
1
INTRODUCTION
 Course Outcomes
 Course Delivery
 Course Assessment
 Lecturers
 Book References
Review of BJT
2
COURSE OUTCOMES
1.
CO1 : Ability to ANALYZE dc , small-signal analysis and
frequency performance of basic configurations of amplifier
(BJT and FET).
2.
CO2 : Ability to DESIGN basic configurations of BJT and FET
amplifiers.
3.
CO3 : Ability to ANALYZE and PERFORM simple design of
classes A, B and AB of BJT and FET power amplifiers in term of
their frequency response, equivalent circuit, thermal
management and gain.
4.
CO4 : Ability to DESCRIBE the principles operation of some
special electronic devices such as Triac, UJT, SCR and ANALYZE
their application circuits.
3
COURSE DELIVERY
Number of Units : 4
Lecture : 3 hours/week x 14 weeks = 42 hours
Lab/Tutorial: 2 hours per week x 14 weeks = 28 hours
4
COURSE ASSESSMENT
• Final Examination
• Mid Term Test 1
• Mid Term Test 2
• Lab Assessment
• Lab test
50%
10%
10%
20%
10%
5
LECTURERS
• DR NIK ADILAH HANIN BT ZAHRI
[email protected]
• DR ONG BI LYNN
[email protected]
• DR AMIZA AMIR
[email protected]
6
BOOK REFERENCES
Textbook:
•
Donald A. Neamen, ‘MICROELECTRONICS Circuit Analysis &
Design’,3rd Edition’, McGraw Hill International Edition, 2007
Reference Books:
•
•
•
Boylestad, R.L. , Nashelsky, L., “Electronic Devices and Circuit
Theory”, 8th Edition, Prentice Hall, 2002.
Thomas L. Floyd, ‘Electronic devices: Conventional Current
Version’, 7th ed.’, Prentice Hall
Gates, E.D. , “Introduction to Electronics”, 5th Edition, Delmar
Cengage Learning.
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INTRODUCTION TO
BJT AMPLIFIER
Bipolar Junction
Transistor (Review)
8
FUNDAMENTALS OF
ELECTRICITY
• Current?
• Voltage?
• Resistance?
• Power?
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FUNDAMENTALS OF
ELECTRICITY
•
Current?
The flow/movement of electrons from negatively charged atoms to
positively charged atoms.
•
Voltage?
The force or difference of potential that causes electrons to
move/flow in a circuit
•
Resistance?
The opposition to the flow of the current
•
Power?
Rate of energy dissipated in a circuit
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CONDUCTORS, INSULATORS &
SEMICONDUCTORS
• Conductors
Materials that contains a large number of free electrons
• Insulators
Materials that prevent the flow of electricity
• Semiconductors
Material that have electrical conductivity between a
conductor and insulators.
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N-TYPE & P-TYPE
SEMICONDUCTORS
• n-type:
 to increase the no. of conduction-band electrons in
intrinsic silicon (such as As, P, Sb)
 majority carrier: electrons
• p-type:
•
to increase the no. of holes in intrinsic silicon (such
as B, In, Ga)
• majority carrier: holes
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WHAT IS PN JUNCTION?
still remember this?
What’s the different between these two figures? Which
one is forward-biased and reverse-biased?
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BIPOLAR JUNCTION
TRANSISTOR
• Three-layer device used to amplify and switch power and
voltage
• Constructed from semiconductors materials such as
silicon and germanium
• 2 types: NPN & PNP
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Remember these symbols?
Still remember about BJT?
Which one is NPN, PNP?
What is C,B,E…?
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BJT CURRENT
I E  I B  IC
The emitter current ( iE ) is the sum of the collector current (iC)
and the base current (iB)
iE  iB  iC
iB << iE and iC
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BJT
• Basic structure and schematic symbol
n
E
p
n
B
approximate
equivalents
E
p
E
C
C
p
C
B
E
C
B
B
C
E
n
B
npn type
transistor
symbols
C
E
B
pnp type
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REFRESH…
• Common-emitter current
gain, β
• Range: 50 < β < 300
• Common-base current
gain, α
• Range: always slightly less
than 1
• The current relationship
between these 2
parameters are as follows:
iE  iC  iB
iC   iB
 iE  (1   )iB
i
iE  (1   ) C

  
iE
iC  
1  



 
But   
1 
 iC  iE



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REFRESH…
• BJT as amplifying device
• B-E junction is forward-biased
• B-C junction is reverse-biased
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BIASING OF BJT
•
Remember…! for normal operation
emitter-base junction is always forwardbiased
AND
collector-base junction is always reversebiased
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CIRCUIT CONFIGURATION
1. Common-base circuit
•
Input enters emitter-base circuit and output leaves from
collector-base circuit
2. Common-emitter circuit
•
Input enters base-emitter circuit and output leaves from
collector-emitter circuit
3. Common collector circuit
•
Input enters base-collector circuit and output leaves from
emitter-collector circuit
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DC ANALYSIS:
COMMON-EMITTER CIRCUIT
Transistor
current-voltage
characteristics of
the commonemitter circuit
23
DC ANALYSIS:
COMMON-EMITTER CIRCUIT
Common-emitter circuit with an
npn transistor
Common-emitter dc equivalent
circuit, with piecewise linear
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parameters
DC ANALYSIS:
COMMON-EMITTER CIRCUIT
VBB  VBE (on)
IB 
RB
Usually VBE(on) = 0.7 V
I C  I B
VCC  I C RC  VCE
Common-emitter dc equivalent circuit
or V CE VCC  I C RC
Look for calculation examples in Neamen (Chapter 5), Example 5.3 & 5.4
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DC ANALYSIS:
LOAD LINE & MODES OF OPERATION
Figure A
Base on Figure A, using KVL around
B-E loop:
VBB  VBE
IB 
 I BQ
RB
Base-emitter junction characteristics and
the input load line
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DC ANALYSIS:
COMMON-EMITTER CIRCUIT
Base on Figure A, 2 end
points of the load line are
found by setting IC = 0
VCC  I C RC  VCE
VCC  I C RC  VCE
So, VCE = VCC = 10 V
When VCE = 0,
IC = VCC/RC = 5 mA
IBQ is the value from the
previous slide = 15 µA
So, ICQ = βIBQ
If β = 200,
ICQ = 3000 µA = 3 mA
V CEQ VCC  I CQ RC
Common- emitter transistor characteristics
and the collector-emitter load line
So, VCEQ = 4 V
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BJT AS AN AMPLIFIER
• Amplification of a small ac
voltage by placing the ac signal
source in the base circuit
• Vin is superimposed on the DC
bias voltage VBB by connecting
them in series with base
resistor RB:
I C   DC I B
• Small changes in the base
current circuit causes large
changes in collector current
circuit
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BJT AS AN AMPLIFIER
(CONT’)
(a) A bipolar inverter circuit to be used as a time-varying amplifier
(b) The voltage transfer characteristic
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SELF- READING
Textbook: Donald A. Neamen, ‘MICROELECTRONICS Circuit
Analysis & Design’,3rd Edition’, McGraw Hill International
Edition, 2007
Chapter 5:The Bipolar Junction Transistor
Page: 287-296, 303-309.
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