1. AMPLIFIERS AND OSCILLATORS
CHAPTER 19
AMPLIFIERS AND OSCILLATORS

2. Transistor AC equivalent circuits
h (hybrid) parameters
r parameters

3. Relation of transistor symbol to r-parameter equivalent

4. The AC bata and
Remember that and

5. COMMON-EMITTER AMPLIFIERS

6. DC equivalent circuit for CE
AC equivalent
(C-short circuit)
DC equivalent
(C-open circuit)

7. r-parameter model

8. A Bypass Capacitor Increases Voltage Gain

9. Phase Inversion and AC input resistance

10. Phase Inversion and AC input resistance
The CE amplifier, the output voltage at the collector is 180°out of phase with the input voltage at the base
The dc input resistance (RIN) can be defined as:

11. Phase Inversion and AC input resistance
The CE amplifier, the output voltage at the collector is 180°out of phase with the input voltage at the base
The dc input resistance (RIN) can be defined as:

12. Current and Power gain for CE
Current gain
is the source current is calculated by
Power gain

13. COMMON-COLLECTOR AMPLIFIERS (EMITTER-FOLLOWER)

14. Voltage gain and Input resistance for CC

15. Current and Power gain for CC
Current gain
is the source current is calculated by
Power gain

16. The Darlington Pair

17. COMMON-BASE AMPLIFIERS

18. Voltage and Current gain for CB
Voltage gain
Current gain

19. Power gain and Input Resistance

20. FET Amplifiers Transconductance of a FET
The transconductance is one factor that determines the voltage gain of a FET amplifier
Sometime called the forward transconductance and is designated with units of Siemens (S)

21. Common-Source (CS) Amplifiers

22. Voltage gain and Input Resistance for CS

23. Common-Drain (CD) or Source-follower Amplifiers

24. Common-Gate (CG) Amplifiers

25. Voltage gain and Input Resistance

26. MULTISTAGE AMPLIFIERS
Multistage gain
Decibel Voltage Gain

27. Multistage Analysis

28. Multistage Analysis (continue)
The voltage gain of the first stage is reduced by the loading of the second stage

29. CLASS OPERATION CLASS A OPERATION CLASS B OPERATION CLASS AB OPERATION
CLASS C OPERATION

30. CLASS A OPERATION

31. CLASS A OPERATION (continue)
A noncentered Q-point Limits Output Swing

32. CLASS B PUSH-PULL AMPLIFIER OPERATION

33. CLASS B PUSH-PULL AMPLIFIER OPERATION (continue)

34. CLASS B PUSH-PULL AMPLIFIER OPERATION (continue)

35. CLASS AB OPERATION

36. CLASS AB OPERATION (continue)

37. CLASS C OPERATION
Class C amplifiers are biased so that conduction occurs for much less than 180°, and are more efficient than either class A or class B

38. OSCILLATORS Oscillator Principles
An oscillator converts electrical energy in the form of DC to electrical energy in the form of AC
Condition for oscillation
The phase shift around the feedback loop must be 0°
The loop gain must be least 1 (unity gain)

39. Oscillator Principles (positive feedback)

40. Start-up conditions

41. The RC Oscillator

42. The Colpitts Oscillator

43. The Hartley Oscillator

44. The Clapp Oscillator

45. The crystal oscillator

46. The crystal oscillator (continue)