1. Electronics Technology Fundamentals Chapter 18 Basic Diode Circuits

2. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 2 18.1 Half-Wave Rectifiers – P1 Rectifier – a diode circuit that converts ac to pulsating dc Filter – a circuit that reduces the variations in the output from the rectifier Voltage Regulator – a circuit designed to maintain a constant power supply output voltage

3. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 3 18.1 Half-Wave Rectifiers – P2 Rectifiers (Continued)

4. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 4 18.1 Half-Wave Rectifiers – P3 Half-Wave Rectifier – a diode that is placed in series between a transformer (or ac line input) and its load. Positive Half-Wave Rectifier – produces a series of positive pulses Negative Half-Wave Rectifier – produces a series of positive pulses

5. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 5 18.1 Half-Wave Rectifiers – P4 Positive and Negative Half-Wave Rectifiers (Continued)

6. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 6 18.1 Half-Wave Rectifiers – P5 Basic Circuit Operation

7. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 7 18.1 Half-Wave Rectifiers – P6 Negative Half-Wave Rectifiers

8. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 8 18.1 Half-Wave Rectifiers – P7

9. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 9 18.1 Half-Wave Rectifiers – P8 Calculating Load Voltage and Current Values where V S(pk) = the peak transformer secondary voltage

10. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 10 18.1 Half-Wave Rectifiers – P9 Average Load Voltage and Current Average Load Voltage (V ave ) – the dc average of the circuit output pulses where 0.318 ~ 1/π

11. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 11 18.1 Half-Wave Rectifiers – P10 Peak Inverse Voltage (PIV) – the maximum amount of reverse bias that will be applied to a diode in a given circuit

12. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 12 18.2 Full-Wave Rectifiers – P1 Full-Wave Rectifier – consists of two diodes that are connected to a center-tapped transformer

13. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 13 18.2 Full-Wave Rectifiers – P2 Basic Circuit Operation

14. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 14 18.2 Full-Wave Rectifiers – P3 Calculating Load Voltage and Current Values where 0.637 ~ 2/π

15. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 15 18.2 Full-Wave Rectifiers – P4 Negative Full-Wave Rectifiers

16. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 16 18.2 Full-Wave Rectifiers – P5 Peak Inverse Voltage

17. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 17 18.2 Full-Wave Rectifiers – P6 Peak Inverse Voltage (Continued) More accurate equation for PIV:

18. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 18 18.3 Full-Wave Bridge Rectifiers – P1 Full-Wave Bridge Rectifier – Most commonly used full-wave rectifier circuit Does not require center-tapped transformer It produces nearly twice the peak output voltage of a full- wave center-tapped rectifier

19. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 19 18.3 Full-Wave Bridge Rectifiers – P2 Circuit Operation – conduction alternates between two diode pairs

20. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 20 18.3 Full-Wave Bridge Rectifiers – P3 Calculating Load Voltage and Current Values

21. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 21 18.3 Full-Wave Bridge Rectifiers – P4 Peak Inverse Voltage (PIV) – approximately equal to V S

22. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 22 18.3 Full-Wave Bridge Rectifiers – P5

23. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 23 18.4 Filtered Rectifiers – P1 Power Supply Filter – a circuit that reduces the variations in the rectifier output signal Ripple Voltage (V R ) – the variation in the output voltage

24. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 24 18.4 Filtered Rectifiers – P2 Basic Capacitive Filter – a capacitor that is connected in parallel with the load

25. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 25 18.4 Filtered Rectifiers – P3 Basic Capacitive Filter (Continued) – the amount of ripple voltage is inversely proportional to the values of the capacitor filter and load resistance

26. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 26 18.4 Filtered Rectifiers – P4 Surge Current At the first instant when a power supply is turned on, the discharged capacitor acts as a short circuit Rectifier current limited by: Winding resistance of the transformer secondary Bulk resistance of the diode Surge Current – high initial current because of low value of series resistances Surge current can be limited by using LC filter

27. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 27 18.4 Filtered Rectifiers – P5 Surge Current (Continued) – LC filter limits surge current

28. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 28 18.4 Filtered Rectifiers – P6 Filter Output Voltages where V pk = the peak rectifier output voltage V r = the peak-to-peak value of ripple voltage

29. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 29 18.4 Filtered Rectifiers – P7 Filter Output Voltages (Continued)

30. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 30 18.4 Filtered Rectifiers – P8 Filter Output Voltages (Continued) where I L = the dc load current t= the time between charging peaks C= the capacitance, in farads

31. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 31 18.4 Filtered Rectifiers – P9 Filter Output Voltages (Continued) – the full- wave rectifier produces half as much ripple as the half-wave rectifier

32. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 32 18.4 Filtered Rectifiers – P10 Filter Effects on Diode PIV

33. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 33 18.4 Filtered Rectifiers – P11 Other Filter Types

34. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 34 18.5 Clippers – P1 Clipper – a diode circuit that eliminates a portion of its input signal (often referred to as a limiter) Series Clipper – is a diode that is connected in series with its load Shunt Clipper – is a diode that is connected in parallel with its load

35. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 35 18.5 Clippers – P2 Series Clippers

36. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 36 18.5 Clippers – P3 Shunt Clippers

37. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 37 18.5 Clippers – P4 The Purpose Served by R S Current-limiting –R S limits current when the diode is forward biased R S is much lower than R l so that the load voltage is approximately equal to the value of V in when the diode is reverse biased

38. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 38 18.5 Clippers – P5 Biased Clippers – is a shunt clipper that uses a dc voltage source to bias the diode Insert Figure 18.34

39. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 39 18.5 Clippers – P6 Biased Clippers (Continued) – a potentiometer is normally used to provide an adjustable value of V B Insert Figure 18.35

40. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 40 18.5 Clippers – P7

41. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 41 18.5 Clippers – P8 Transient Protection: A Clipper Application Transient – an abrupt current or voltage spike that has an extremely short duration

42. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 42 18.6 Clampers (DC Restorers) – P1 Clamper – a circuit designed to shift a waveform either above or below a given reference voltage without distorting the waveform

43. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 43 18.6 Clampers (DC Restorers) – P2

44. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 44 18.6 Clampers (DC Restorers) – P3 Clamper Operation Capacitor Charge Time: Capacitor Discharge Time:

45. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 45 18.6 Clampers (DC Restorers) – P4 Clamper Operation (Continued)

46. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 46 18.6 Clampers (DC Restorers) – P5 Negative Clampers Versus Positive Clampers

47. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 47 18.6 Clampers (DC Restorers) – P6 Biased Clampers – a circuit that allows a waveform to be shifted so that it falls above or below a dc reference other than 0 V

48. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 48 18.6 Clampers (DC Restorers) – P7 Biased Clampers (Continued)

49. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 49 18.7 Voltage Multipliers – P1 Voltage Multiplier – a circuit that provides a dc output that is a whole-number multiple of its peak input voltage

50. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 50 18.7 Voltage Multipliers – P2 Half-Wave Voltage Doublers

51. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 51 18.7 Voltage Multipliers – P3 Half-Wave Voltage Doublers (Continued)

52. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 52 18.7 Voltage Multipliers – P4 Full-Wave Voltage Doublers

53. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 53 18.7 Voltage Multipliers – P5 Voltage Triplers

54. Electronics Technology Fundamentals, 3 rd ed. Paynter and Boydell © 2009 Pearson Higher Education, Upper Saddle River, NJ 07458. All Rights Reserved. 54 18.7 Voltage Multipliers – P6 Voltage Quadrupler