;

Lecture Notes - Chapter 9

Oscillators

(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).

  • Understanding Oscillators
    • Discuss the three sections of an oscillator.
    • Introduce the term: negative feedback (figure 9.3).
    • Introduce the term: positive feedback (figure 9.4).
      • Positive feedback can cause an amplifier to oscillate even when there is no external input.
    • Introduce the term: resonant load (figure 9.8).
  • Feedback
    • Discuss the feedback method used in a Colpitts oscillator (figure 9.11 (1)).
    • Discuss the feedback method used in a Hartley oscillator (figure 9.11 (2)).
    • Discuss the feedback method used in an Armstrong oscillator (figure 9.11 (3)).
  • The Colpitts Oscillator
    • Discuss the Colpitts oscillator circuit (figure 9.15).
      • Feedback is taken from a connection between the two capacitors in the resonant circuit.
    • Review the equation used to calculate the resonance frequency of a Colpitts oscillator.
    • Review the equation used to determine the fraction of the output voltage used as feedback in the Colpitts oscillator.
  • Project 9.1: The Colpitts Oscillator
    • Discuss the objective of the project.
    • Review the circuit diagrams (figure 9.18 and 9.19).
    • Review the test setup (figure 8.21).
    • Discuss how to calculate the frequency from the measured period.
  • The Hartley Oscillator
    • Discuss the Hartley oscillator circuit (figure 9.27).
      • Feedback is taken from a tap partway down the coil, or if two inductors are used, a connection between the two inductors in the resonant circuit.
  • Project 9.2: The Hartley Oscillator
    • Discuss the objective of the project.
    • Review the circuit diagram (figure 9.30).
    • Review the test setup (figure 9.32)
  • The Armstrong Oscillator
    • Discuss the Armstrong oscillator circuit (9.35).
  • Simple Colpitts Oscillator Design Procedure
    • Review the equation to determine the value of C1.
    • Discuss the calculation to determine the value of C2.
    • Discuss the calculation to determine the value of RC.
    • Discuss the calculation to determine the value of CC and CB.

 

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

Copyright 2007 - 2012 Hawk's Perch Technical Writing, LLC - All rights reserved