1. Experiment # 8 EE 312 & 352 Introductory Electronics Laboratory November 1, 1999 InputFilterRegulationLoad

2. Objective: Design, construct, and test a dc power supply. The power supply includes a transformer, diodes, and a filter. All were investigated in previous experiments. This the major design project in the course.

3. Transformer FilterRegulator Alternator or Power Company Rectifier Load t v Input: 120 VAC RMS, 60 Hz Steps the input voltage up and down as needed Convert the ac to a pulsing dc Low-pass type for removing voltage variation Keeps voltage constant regardless of load change DC-VOLTAGE POWER SUPPLY OPERATION

4. Transformer FilterRegulatorRectifier Load Power Company t v 167 118 V rms 16.7 ms or 60Hz

5. Transformer FilterRegulatorRectifier Load Alternator or Power Company t v 167 118 V rms 16.7 ms or 60Hz t v 25.5 18 V rms 16.7 ms or 60Hz

6. Transformer FilterRegulatorRectifier Load Alternator or Power Company t v R Load t v half-wave rectifier full-wave rectifier 60Hz 120Hz

7. Transformer FilterRegulatorRectifier Load Alternator or Power Company t v 25.5 18 V rms 16.7 ms or 60Hz ~ 0.6V t v half-wave rectifier 24.9 60 Hz 12.45 V rms t

8. Transformer FilterRegulatorRectifier Load Alternator or Power Company InputFilterRegulationLoad stage 1 stage 2

9. t v t t v t V max ripple InputFilterRegulationLoad stage 1 without C with C C

10. t v V max ripple t V DC 0 ? ?

11. stage 2 V across R < 25% of V input One or more filter sections are usually used to reduce the amplitude of the ripple. The filter used in this experiment is a single-section low-pass RC filter. InputFilterRegulationLoad C R V input usually tolerable

12. Ripple Reduction Factor: V in V out

13. Transformer FilterRegulatorRectifier Load Alternator or Power Company You are asked to design and built a 12 V dc regulated power supply. In this experiment you use a Zener diode that breaks down at 12 V.

14. IDID VDVD Forward Characteristics Reverse Characteristics 12Volts breakdown voltage ~ ~ I Max IzIz I Load I DC IzIz

15. IDID VDVD ~ ~ I Max R Load Rs RzRz I DC I Load IzIz R Load Rs RzRz I DC I Load IzIz Voltage Divider = V input

16. Transformer FilterRegulator Alternator or Power Company Rectifier Load t v Summary

17. Procedures: I- Design, construct, and test a dc power supply. II- Simulate dc power supply. I

18. Components: 18 Volts Transformer Variac Bridge rectifier (use 1 diode) Zener diode (Vbd=12Vdc, 1N4742) 12 Watt, 1000 Ohm, variable resistor 2 Resistor Substitution Boxes 50, 100, and 200 UF Fixed Capacitors

19. 1- Design, construct, test a dc power supply Suggestion: Zener diode current = 21 mA (At this current, the Zener resistance is 9 ohms) V Load =12 V dc I Load = 50mA Peak to peak ripple voltage from the input stage < 20% Peak to peak ripple voltage at the load <= 1% R? C? R? C?

20. V Load =12 V dc I Load = 50mA Peak to peak ripple voltage from the input stage < 20% Peak to peak ripple voltage at the load <= 1% R? C? R Load ? C?

21. V Load =12 V dc I Load = 50mA Peak to peak ripple voltage from the input stage < 20% Peak to peak ripple voltage at the load <= 1% R? C? I DC Iz=21mA

22. V Load =12 V dc I Load = 50mA Peak to peak ripple voltage from the input stage < 20% Peak to peak ripple voltage at the load <= 1% R? C? CI?CI? I DC = 71mA Iz=21mA t v V max ripple t V DC 0

23. t v V max = 24.9 ripple t V DC =22.4 V 0 < 24.9 x 0.2=4.98 V 20% ripple V min =19.92

24. V Load =12 V dc I Load = 50mA Peak to peak ripple voltage at the load <= 1% RF?RF?Rs? CF?CF? C I =250uF I DC = 71mA Iz=21mA V DC =0.6V+I DC (R F +R S )+V z 22.4=0.6+.071(R F +R S )+12 RF+RS = 138.03 ohms

25. V Load =12 V dc I Load = 50mA Peak to peak ripple voltage at the load <= 1% RF?RF?Rs? CF?CF? C I =250uF I DC = 71mA Iz=21mA 20% ripple 6.6% ripple &

26. V Load =12 V dc I Load = 50mA Peak to peak ripple voltage at the load <= 1% R F =75 Rs=63 C F=250uF C I =250uF I DC = 71mA Iz=21mA 0.1% ripple 2% ripple

27. 2- Simulation of Part I Simulate the dc power supply! Show output wave form at points 1, 2, and 3. Comnpare these waveforms with your experiment. 123

28. V Load =12 V dc I Load = 50mA R F =105 Rs=33 C F=250uF C I =250uF Iz=21mA ? Variac Transformer 18.0 V 118.4 Vvariable

29. Report is required for EE 312 & 352