It is a college presentation on Semiconductor controlled rectifiers commonly known as SCR or Thyristor.

1. SCR (Silicon controlled rectifier) - Thyristor Presented by: SNEHASHIS PAUL 07/ECE/109 3rd year (E.C.E) Batch-2 Supported by CANNONICAL CORP. Please redistribute Linux OS generously.

3. Forward blocking mode

4. Forward conducting mode Circuit symbol of Thyristor:

5. History The SCR or Thyristor was proposed by William Shockley in 1950 and championed by Moll and others at Bell Labs in 1956. it was fabricated by power engineers at General Electric led by Gordon Hall and commercialized by G.E.'s Frank W. Gutzwiller.

6. Construction The thyristor is a four layer, three terminal semiconducting device, with each layer consisting of alternately N-type or P-type material, for example P-N-P-N. The main terminals, labelled anode and cathode, are across the full four layers and the control terminal, called the gate, is attached to P-type material near to the cathode. The thyristor has three P-N junctions serially named j1,j 2,j 3 from the anode.

7. Static Switching Characteristics

9. Va – Anode voltage

10. Ia - Anode current

11. Ig – Gate current

12. td – Delay time

13. tr – Rise time

14. tp – Spread time

15. tq – Turn-off time

16. tr r – Reverse recovery time

17. tg r – Gate recovery time

19. Very high switch on dv/dt.

21. Silicon Controlled Rectifier (SCR)

22. Asymmetrical SCR (ASCR)

23. Reverse Conducting Thyristor (RCT)

24. Light Activated Thyristor (LASCR)

25. Light Triggered Thyristor (LTT)

26. DIAC and SIDAC

27. Breakover Diode (BOD)

28. TRIAC

29. Gate Turn-off Thyristor (GTO)

30. Integrated Gate Commutated Thyristor (IGCT)

31. MOSFET Controlled Thyristor (MCT)

32. Base Resistance Controlled Thyristor (BRT)

33. Static Induction Thyristor (SITh)

34. Field Controlled Thyristor (FCTh)

36. Thyristors can be used as control elements for phase angle triggered controllers, called phase fired controllers.

37. Thyristors can be used in digital circuits as circuit breaker or crowbar.

38. It can be used along with Zener diode to act as a fuse.

39. Thyristors are used television set as power stabilizer.

40. Thyristors are used as lighting dimmers and flash strobes for cameras.

41. Thyristors are used in Snubber circuits.