1. Unit –III Waveform Generators
-14 Marks

2. Course Outcome
Use BJT as Waveform Generator

3. Introduction to Oscillators:
“An amplifier with positive feedback acts as
an oscillator”. .
AEI403.23

4. Definition :
“An oscillator is just an electronic circuit which converts dc energy into ac energy of required frequency”. Or
“An oscillator is an electronic circuit which produces an ac output without any input”.
AEI

5. Classification of Oscillators
RC Oscillator
RC phase shift
Wein Bridge Oscillator
LC Oscillator
Hartley
Colpitts
Clapp
Crystal Oscillator

6. Bakhausen Criteria

7. Bakhausen Criteria

8. RC Phase Shift Oscillator

9. At some particular frequency fo,the phase shift of each section is 60º,so that the total phase-shift produced by the RC network is (3*60º)=180º.
The frequency of oscillations is given by 1
f 
2RC 6
Where R1=R2=R3=R
C1=C2=C3=C.

10. Pierce Crystal oscillator

11. Miller Crystal Oscillator

12. Miller Sweep Generator

13. Bootstrap Sweep Generator