1. 1 Teaching Innovation - Entrepreneurial - Global The Centre for Technology enabled Teaching & Learning, N Y S S, India DTEL DTEL (Department for Technology Enhanced Learning)

2. DEPARTMENT OF ELECTRICAL ENGINEERING IV-SEMESTER POWER DEVICES & MACHINES 2 CHAPTER NO. - 1 THYRISTOR

3. CHAPTER 1:- SYLLABUSDTEL SCR – Construction & Operation 1 Transistor analogy 2 Static,Dynamic &Switching Characteristics 3 Gate characteristics 4 3 Triggering requirements & techniques 5

4. CHAPTER-1 SPECIFIC OBJECTIVE / COURSE OUTCOMEDTEL Understand the basics of different components used in Power Electronics. 1 Understand the working and characteristics of different power devices along with their applications in Electronic circuits. 2 4 The student will be able to:

5. LECTURE 1:- SCR – Construction & OperationDTEL 5 5 SYMBOL & STRUCTURE

6. LECTURE 1:- SCR – Construction & OperationDTEL 6 6 Fig. Cross-sectional view of alloy-diffused SCR (Mesa type)

7. DTEL 7 LECTURE 1:- Two Transistor analogy

8. DTEL 8 THANK YOU LECTURE 1

9. DTEL 9 LECTURE 2:- Static V-I Characteristics Of SCR

10. DTEL 10 LECTURE 2:- Static V-I Characteristics Of SCR

11. DTEL 11 THANK YOU LECTURE 2

12. DTEL 12 LECTURE 3:- Dynamic Characteristics Of SCR Turn –On characteristics

13. DTEL 13 LECTURE 3:- Dynamic Characteristics Of SCR Turn –Off characteristics

14. DTEL 14 THANK YOU LECTURE 3

15. DTEL 15 LECTURE 4:- Gate Characteristics Of SCR

16. DTEL 16 Triggering Methods :  Voltage Triggering  Thermal Triggering  Radiation Triggering  dv/dt triggering  Gate triggering LECTURE 5:- Triggering Requirements & Techniques

17. DTEL 17 LECTURE 5

18. DTEL 18 (i)Voltage Ratings (ii)Current Ratings (iii) Thermal Ratings (iv) Turn-on & turn off time LECTURE 5:- SCR Ratings

19. DTEL 19 UNIJUNCTION TRANSISTOR (UJT) LECTURE 6:- Triggering Techniques

20. DTEL 20 THANK YOU LECTURE 6

21. DTEL 21 UJT AS RELAXATION OSCILLATOR LECTURE 7:- Triggering Techniques

22. DTEL 22 PROGRAMMABLE UNIJUNCTION TRANSISTOR LECTURE 7:- Triggering Techniques

23. DTEL 23 PUT AS RELAXATION OSCILLATOR LECTURE 7:- Triggering Techniques

24. DTEL 24 LECTURE 7

25. DTEL 25 LECTURE 8:- Triggering Techniques Fig. R- firing circuit and associated voltage waveforms

26. DTEL 26 LECTURE 8:- Triggering Techniques Fig. (a) R-C firing circuit (b) Voltage waveforms

27. DTEL 27 THANK YOU LECTURE 6

28. DTEL 28 LECTURE 8:- Triac Fig. (a) Construction (b) Symbol

29. DTEL 29 LECTURE 8:- Triac Characteristics Fig. (c) Characteristics of a Triac

30. DTEL 30 LECTURE 8:- Triggering Modes Of Triac MODE 1 MODE 2

31. DTEL 31 LECTURE 8:- Triggering Modes Of Triac MODE 3 MODE 4

32. DTEL 32 LECTURE 8:- Phase Control Of TRIAC using DIAC

33. DTEL 33 Fig. waveforms of phase control of Triac using Diac LECTURE 8:- Phase Control Of TRIAC using DIAC

34. DTEL 34 THANK YOU LECTURE 8