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EEL 3304C Fall 2007: Introduction to Electronic Circuits
• Instructor: Prof. Rizwan Bashirullah• Preview
– Goals– Logistics
• Requirements/expectations
– Introduction• Reading
– Chapter 1 (Intro) – Chapter 2 (Operational Amplifiers)
Textbook
Title: Microelectronic CircuitsAuthor: A.S. Sedra & K.C. SmithPublication date and edition: 5th ed, Oxford University Press, 2004ISBN number: 0-19-514251-9
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Goals• Concise
– To understand and apply Fundamentals of electronic circuits and systems
• Both theoretical and experimental (practical—lab)
• Background– EEL 3111C Circuits 1
• Linear• Passive
– Electronic Devices & Circuits• Nonlinear• Active
Logistics
• Class www sites:– http://www.icr.ece.ufl.edu/teaching/EEL3304-F07/3304home.htm
• Syllabus, course calendar, announcements, homeworks, solutions
– http://lss.at.ufl.edu• Grades, secure content• Available to all registered students
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Course Focus
1. Input signals, amplifier models (Chapter 1)2. Nearly ideal electronic circuit—Operational amplifier
and its Basic Uses (Chapter 2)3. Electron device #1—Diode and its Basic Circuit
Applications (Chapter 3)4. Electron device #2—MOS Transistor and its Basic
Circuit Applications (Chapter 4)5. Electron device #3—Bipolar Junction Transistor and its
Basic Circuit Applications (Chapter 5)6. Single-stage integrated circuit amplifiers (Chapter 6)7. Differential and multi-stage amplifiers (Chapter 7)
What’s next? EEL 4306C, EEL 4310, etc.
Review: Thevenin Equivalent• Replace a complex network with a voltage
source and series resistance• Measure the open circuit voltage at the
network terminals • This voltage becomes the Thevenin
equivalent voltage • "Zero" all independent supplies
– short circuit voltage supplies – open circuit current supplies
• Measure the resulting resistance between the terminals Thevenin equivalent resistance – Might be able to do this by inspection
series/parallel resistors – apply a test voltage and compute test
current
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Simple Example of Thevenin Equivalent
• Circuit with a 1V supply in series with 5k and 10k resistor -10k across network terminals
• Open circuit voltage is 1V * 10k / 15k = 0.66V
• Zero supplies - short circuit voltage supply - 10k in parallel with 5k = 3.33k
• Equivalent is a 0.66V supply with a 3.33k resistor in series
Review: Norton’s Theorem• Replace a complex network with a
current source and parallel resistor• Measure the short-circuit current across
terminals • This current is the Norton equivalent
current • "Zero" all independent supplies
– short circuit voltage supplies – open circuit current supplies
• Measure the resulting resistance between the terminals Norton equivalent resistance – Might be able to do this by inspection
series/parallel resistors – apply a test voltage and compute test current
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Simple Example of Norton Equivalent
• Circuit with a 1V supply in series with 5k and 10k resistor - 10k across network terminals
• Short circuit current is 1V / 5k = 200uA
• Zero supplies - short circuit voltage supply - 10k in parallel with 5k = 3.33k
• Equivalent is a 200uA supply with a 3.33k resistor in parallel
• Continuous-time signal (Analog)• Sampling→ Discrete time• Finite number of digits → Digital
Figure 1.7 Sampling the continuous-time analog signal in (a) results in the discrete-time signal in (b).
sensorNonelectricalElectricalSignal (t)
Signals
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Fundamental Building Block for Analog (and also Digital Systems)
• Amplifier• Circuit Symbol
Figure 1.10 (a) Circuit symbol for amplifier. (b) An amplifier with a common terminal (ground) between the input and output ports.
Applications• What are some applications of amplifiers?
http://electronics.howstuffworks.com/radio8.htm
Amplitude Modulation
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Figure 1.13 An amplifier transfer characteristic that is linear except for output saturation.
What does it mean to amplify a signal?
Linear and non-linear regions of operation
Amplifier Gain and DC Bias
)()( tVVtV iII +=Total
InstanteousValue
DCQuiescent AC
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Amplifier Gain• Voltage Gain: Av =
(dB) 20log |Av| dB• Current Gain : Ai =
(dB) 20log |Ai| dB• Power Gain: Ap =Av AI
(dB) 10log |Ap|dB
I
o
VV
I
o
ii
[ ])()(21)( dBAdBAdBA IVP +=
Note: multiplication of two numbers is equivalent to adding their logarithms
A few words about dB• When is the Gain in dB a negative number?
– Inverting amplifier (180 degrees phase difference between input and output)
– Or when the amplifier is attenuating• dB is unitless:20log (V/V) or 20log (I/I) or
10log(W/W)• Find the log of 0.1, 1, 10 , 100, • If the gain is -6dB, what is the gain in V/V• If gain is -3dB, what is the gain in V/V
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Amplifier Models• Voltage Amplifier• Current Amplifier• Transconductance Amplifier• Tranresistance Amplifier
1. Voltage Amplifier
• Avo = open circuit voltage gain
• Ri= input resistor• Ro= output resistor
⎟⎠⎞
⎜⎝⎛=
=VV
VV
oii
o
0
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With Signal and Load
si
isi RR
RVV
+=
oL
Livo RR
RVAV
o +=
s
o
VV
≡oL
L
si
iv RR
RRR
RA
o ++=
• Voltage Buffer Amp– Ri high, Ro low– Unity Gain Avo = 1
• Find overall Gain
2. Current Amplifier Model
• Ais = Short Circuit Current Gain
⎟⎠⎞
⎜⎝⎛=
=AA
ii
oVi
o
0
• Current Buffer Amp– Ri low, Ro high– Unity gain, Ais = 1
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3. Transconductance Amp Model
• Gm = Short Circuit Transconductance
⎟⎠⎞
⎜⎝⎛=
=VA
Vi
oVi
o
0
4. Transresistance Amp Model
• Rm = Open Circuit Transresistance
⎟⎠⎞
⎜⎝⎛=
=AV
iV
oVi
o
0
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Summary• Goals• Logistics• Electronic Circuits• Signal sources• Amplifier models