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Lecture Notes - Chapter 8

Transistor Amplifiers

(These Lecture Notes are for courses using the book the Complete Electronics Self-Teaching Guide with Projects. Instructors of courses using that text are permitted to use these Lecture Notes as-is or adapt them for their use).

• Working with Transistor Amplifiers
• Discuss the relationship between IC and VC (figure 8.2).
• Introduce the terms: linear region
• Operating a transistor in the linear region results in an output signal that is free of distortion.
• Discuss the amplification of an AC signal in a transistor circuit (figure 8.4).
• Review the equation to calculate the voltage gain (AV).
• Discuss the limitations of the simple amplifier circuit shown in figure 8.2.
• A Stable Amplifier
• Discuss the addition of R2 and RE to the amplifier circuit that result in the circuit shown in figure 8.5.
• R1 is added to ensure the stability of the DC bias point.
• RE is added to ensure the stability of AC gain.
• Discuss the equation for the AC voltage gain for this circuit.
• Biasing
• Discuss the calculations to determine R1, R2 and RE for the circuit shown in figure 8.8.
• Project 8.1: The Transistor  Amplifier
• Review the circuit diagram (figure 8.12).
• Review the test setup (figure 8.15).
• Emitter Bypass Capacitor
• Discuss the addition of an emitter bypass capacitor to a transistor amplifier circuit (figure 8.18).
• Discuss the different paths taken by DC vs. AC signals when an emitter bypass capacitor is used (figure 8.19).
• Review the equation used to calculate the AC voltage gain for an amplifier using an emitter bypass capacitor.
• Discuss the change in voltage amplification that occurs when an emitter bypass capacitor is used.
• The Emitter Follower
• Review the emitter follower circuit (figure 8.23).
• Discuss the calculations to determine R1 and R2.
• Discuss the voltage gain of the emitter follower circuit.
• Discuss the difference between the input resistance and output resistance of  an emitter follower circuit.
• Discuss the advantages of using the emitter follower circuit when driving a load (figure 8.25).
• Analyzing an Amplifier
• Discuss the equations used to calculate VB, IC, VC and AV for a amplifier circuit (figure 8.27).
• Discuss the difference in AV for the circuit with and without an emitter bypass capacitor.
• The JFET as an Amplifier
• Review the transfer curve for a JFET (figure 8.31).
• Discuss the equation to calculate the drain current.
• Review the JFET common source amplifier circuit (figure 8.32).
• Introduce the term: transconductance (gm).
• Discuss the equation used to calculate the AC voltage gain, using gm.
• Discuss the calculations used to determine RD and RS for the circuit shown in figure 8.33.
• The Operational Amplifier
• Discuss the advantages of using operational amplifiers.
• Review the op-amp circuit shown in Figure 8.35.
• Discuss the equation used to calculate the AC voltage gain for this circuit.
• Project 8.2: The Operational Amplifier
• Discuss the project objective.
• Review the circuit diagram (figure 8.38).
• Review the test setup (figure 8.40).

This page includes material extracted, by permission of the publisher, Wiley Publishing, from Complete Electronics Self-Teaching Guide with Projects, ISBN: 9781118217320.