Lectures:
Lecture No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
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22
Contents Discussed in Class
Readings from References and Handouts
Further Readings
Revision on BJTs
- Types of Transistors
- 2 types of BJTs
- Relationship among base, emitter and collector currents
- Region of operations of BJT
- Detailed BJT characteristics (input, transfer and output characteristics)
Small-signal characteristics of BJT:
- Trans-conductance of BJT (from transfer characteristics)
- Early effect and output resistance (from output characteristics)
- Input resistance (from input characteristics)
- Small-signal model of BJT
Classification of Amplifiers:
- Voltage Amplifier
- Current Amplifier
- Trans-conductance Amplifier
- Trans-resistance Ampifier
The Feedback Concept:
- Representation of any single-loop feedback connection around a basic amplifier
- Types of signal source
- Feedback Network
- Voltage and Current sampling networks
- Series and Shunt mixing networks
Transfer gain with feedback:
- stability of gain with feedback
- Definition of Negative Feedback
- Advantages of Negative Feedback
- Desensitivity of Transfer Amplification
- Fundamental Assumptions of Feedback Amplifiers
- Feedback Amplifier Topologies (Voltage-series, Current-Series, Voltage-shunt, Current-shunt)
Text Ref1: Ch. 13 Feedback Amplifiers
13-2. The Feedback Concept
13-3. The Transfer Gain with Feedback
Text Ref1: Ch. 13 Feedback Amplifiers
13-2. The Feedback Concept
13-3. The Transfer Gain with Feedback
13-4. General Characteristics of Negative-Feedback Amplifiers
Effect on input resistance with feedback
Effect on output resistance with feedback
Text Ref1: Ch. 13 Feedback Amplifiers
13-5. Input Resistance
Text Ref1: Ch. 13 Feedback Amplifiers
13-6. Output Resistance
Text Ref1: Ch. 13 Feedback Amplifiers
13-7. Method of Analysis of a Feedback Amplifier
Identification of Feedback Topologies
- Identification of Feedback Network
- Identification of type of mixing
- Identification of type of sampling
Identification of Feedback Topologies (continued)
Text Ref1: Ch. 13 Feedback Amplifiers
13-7. Method of Analysis of a Feedback Amplifier
Handout1: Ch. 8 Small Signal Amplifiers
8.4.2 h-parameter Equivalent circuit
Text Ref1: Ch. 13 Feedback Amplifiers
13-8. Voltage-series Feedback (The Emitter Follower)
Text Ref1: Ch. 13 Feedback Amplifiers
13-10. Current-series Feedback
h-parameter model of BJT
Example of Feedback Topology: Voltage-series
Example of Feedback Topology: Current-series
Example of Feedback Topology: Voltage-shunt
Example of Feedback Topology: Current-shunt
Example of Feedback Topology: Voltage-series (2)
Example of Feedback Topology: Voltage-series (2) Contd.
Exam on Feedback Amplifiers
Amplifier Classes:
- Class-A, Class-B, and Class-C
Biasing a Transistor for amplifier operation:
-Various biasing methods (Self-bias, Fixed-bias) and bias point calculations
Variation of Q-point with circuit parameters:
- base current, load resistance and supply voltage
Class-A amplifier Operation
- Setting Q-point for class-A operation
- Finding equation for load line
- Finding voltage and current waveforms using load line
- Explanation of phase relationships between current and voltage waveforms
Class-A amplifier:
- Maximum Efficiency Calculation of series-fed class-A amplifier
Two load lines:
- AC and DC load line of a Class-A amplifier
Transformer-coupled Class-A amplifier:
- DC and AC load lines
- Maximum Efficiency calculation
Class-B amplifier operation
Class-B Push-Pull Configuration and its operation:
- Crossover distortion and its reasons
- Maximum Efficiency Calculations
Class AB amplifier:
- Voltage-divider bias and thermal runaway
- Diode bias
Class C Power Amplifier and its operation:
- Tuned class-C amplifier, its current and voltage waveforms, tuning frequency and uses
Example1: Calculating efficiency of series-fed Class-A amplifier
Example2: Calculating efficiency of transformer-coupled Class-A amplifier
Amplifier Distortion:
- Concept of fundamental and harmonic frequencies
- Harmonic Distortion Components
- Total Harmonic Distortion
- Power of Signal having distortion
Text Ref1: Ch. 13 Feedback Amplifiers
13-12. Voltage-shunt Feedback
Text Ref1: Ch. 13 Feedback Amplifiers
13-11. Current-shunt Feedback
Text Ref2:
Ch. 4 DC Biasing-BJTs
4.3 Fixed Bias Configuration
- Forward-bias of Base-Emitter
- Collector-Emitter Loop
- Load-Line Analysis
4.4 Emitter-bias Configuration
- Base-Emitter Loop
- Collector-Emitter Loop
4.5 Voltage-divider bias Configuration
- Exact Analysis
Ch. 12 Power Amplifiers
12.1 Introduction-Definitions and Amplifier Types
Table 12.1 Comparison of Amplifier Classes based on operating cycle and power efficiency
Text Ref2: Ch. 12 Power Amplifiers
12.2 Series-Fed Class-A amplifier
- DC Bias Operation
- AC Operation
Text Ref2: Ch. 12 Power Amplifiers
12.2 Series-Fed Class-A amplifier
- Power considerations: Input Power, Output Power, Efficiency, Maximum Efficiency
External Ref3: Ch. 12 Power Amplifiers
12.2 Two Load Lines
- DC Load line
- AC load line
- Clipping of large signals
Text Ref2: Ch. 12 Power Amplifiers
12.3 Transformer-coupled Class A amplifier
- Transformer action: Current, voltage and impedance transformation
- Operation of amplifier stage: DC load line, Q-point, AC load line, Signal Swing and output AC power, Efficiency, Maximum theoretical efficiency
External Ref3: Ch.12 Power Amplifiers
12.5 Class B Push-pull Emitter Follower
- Crossover distortion
Text Ref2: Ch. 12 Power Amplifiers
12.4 Class B Amplifier operation
- Input (DC) power
- Output (AC) power
- Efficiency
- Maximum power considerations
External Ref3: Ch.12 Power Amplifiers
12.6 Biasing Class B/AB amplifiers
- Voltage-divider bias
- Diode bias
12.8 Class C operation
Text Ref2: Ch. 12 Power Amplifiers
- Example 12.1
- Example 12.4
12.6 Amplifier Distortion
- Harmonic Distortion
(Fig. 12.21 Graphical representation of a distorted signal through the use of harmonic components)
- Total Harmonic Distortion
- Power of Signal having distortion