Chapter (3) - Bipolar Junction Transistor

Introduction to Transistor

1. Bipolar Junction Transistors Chapter 3 ENGR. JEZER E. ILAO, ECT

2. The Invention BIPOLAR JUNCTION TRANSISTORS

3. The Structure Bipolar : both electrons and holes are involved in current flow. Junction : has two p-n junctions. Transistor : Transfer + Resistor. It can be either n-p-n type or p-n-p type. Has three regions with three terminals labeled as: emitter, base and collector BIPOLAR JUNCTION TRANSISTORS

4. BIPOLAR JUNCTION TRANSISTORS The Structure: npn & pnp Base is made much narrow. Emitter is heavily doped ( p + , n + ). Base is lightly doped ( p - , n - ). Collector is lightly doped ( p, n ).

5. BIPOLAR JUNCTION TRANSISTORS Circuit Symbol Transistors can be constructed as two diodes that are connected together.

6. BIPOLAR JUNCTION TRANSISTORS Circuit Symbol Layout and Circuit Symbol: n-p-n Transistor

7. BIPOLAR JUNCTION TRANSISTORS Circuit Symbol Layout and Circuit Symbol: p-n-p Transistor The arrow indicates the direction of current flow. The current flows from emitter to collector in an p-n-p transistor. The arrow points towards the n-type. So the base is n-type and transistor is p-n-p type.

8. BIPOLAR JUNCTION TRANSISTORS Modes of Operation Based on the bias voltages applied at the two p-n junctions, transistors can operate in three modes : 1. Cut-off (both EB and CB junctions are reversed biased) 2. Saturation (both EB and CB junctions are forward biased) 3. Active mode (EBJ is forward biased and CBJ is reversed biased) Cut-off and Saturation modes are used in switching operation. Active mode is used in amplification purposes.

9. BIPOLAR JUNCTION TRANSISTORS Modes of Operation

10. BIPOLAR JUNCTION TRANSISTORS BIASING

11. BIPOLAR JUNCTION TRANSISTORS OPERATION

12. BIPOLAR JUNCTION TRANSISTORS TRANSISTORS CURRENTS

13. BIPOLAR JUNCTION TRANSISTORS BJT CHARACTERISTICS AND PARAMETER

14. BIPOLAR JUNCTION TRANSISTORS

15. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

16. BIPOLAR JUNCTION TRANSISTORS BJT Circuit Analysis

17. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

18. BIPOLAR JUNCTION TRANSISTORS CUTOFF

19. BIPOLAR JUNCTION TRANSISTORS Modes of Operation Cut-off Both the junctions are reversed biased. No current can flow through either of the junctions. So the circuit is open. Ideal model of BJT in cut-off.

20. BIPOLAR JUNCTION TRANSISTORS Modes of Operation SATURATION

21. BIPOLAR JUNCTION TRANSISTORS Modes of Operation Saturation: Ideal Model Ideal model of BJT in saturation. Both the junctions are forward biased. So the equivalent circuit can be represented by short-circuit between the base, emitter and collector.

22. BIPOLAR JUNCTION TRANSISTORS Modes of Operation Saturation: Practical Model V CE (sat) is in the range of 0.1 to 0.2 V, as V BC and V BE are both approximately equal to the diode forward drop.

23. BIPOLAR JUNCTION TRANSISTORS DC Load Line

24. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

25. BIPOLAR JUNCTION TRANSISTORS The BJT as an AMPLIFIER Voltage Amplification

26. BIPOLAR JUNCTION TRANSISTORS The BJT as an AMPLIFIER Voltage Amplification

27. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

28. BIPOLAR JUNCTION TRANSISTORS SWITCHING Operation

29. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

30. BIPOLAR JUNCTION TRANSISTORS SUMMARY

31. BIPOLAR JUNCTION TRANSISTORS SUMMARY

32. BIPOLAR JUNCTION TRANSISTORS SUMMARY

33. BIPOLAR JUNCTION TRANSISTORS KEY FORMULAS

34. BIPOLAR JUNCTION TRANSISTORS PRACTICE PROBLEM

35. BIPOLAR JUNCTION TRANSISTORS PRACTICE PROBLEM

36. Transistor Bias Circuits ENGR. JEZER E. ILAO, ECT

37. BIPOLAR JUNCTION TRANSISTORS DC Bias

38. BIPOLAR JUNCTION TRANSISTORS

39. BIPOLAR JUNCTION TRANSISTORS DC Load Line

40. BIPOLAR JUNCTION TRANSISTORS Linear Operation

41. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

42. BIPOLAR JUNCTION TRANSISTORS VOLTAGE-DIVIDER BIAS

43. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

44. BIPOLAR JUNCTION TRANSISTORS Loading Effects of Voltage-Divider Bias

45. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

46. BIPOLAR JUNCTION TRANSISTORS Thevenin’s Theorem Applied to Voltage-Divider Bias

47. BIPOLAR JUNCTION TRANSISTORS Voltage-Divider Biased PNP Transistor

48. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

49. BIPOLAR JUNCTION TRANSISTORS Emitter Bias

50. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

51. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

52. BIPOLAR JUNCTION TRANSISTORS Base Bias

53. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

54. BIPOLAR JUNCTION TRANSISTORS Emitter-Feedback Bias

55. BIPOLAR JUNCTION TRANSISTORS EXAMPLE

56. BIPOLAR JUNCTION TRANSISTORS Collector-Feedback Bias

57. BIPOLAR JUNCTION TRANSISTORS EXAMPLE