# Neets Module 6 Assignment 3

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1. What are the four basic sections to a power supply?
• Transformer,
• Rectifier
• Filter
• Regulator.
2. What is the purpose of the regulator?
To maintain a constant voltage to the load.
3. What are the purposes of the transformer in a power supply?
It couples the power supply to the ac line voltage, isolates the ac line voltage from the load, and steps this voltage up or down to the desired level.
4. For what are the low voltage windings in a transformer used?
Filament voltage to the electron tubes.
5. For what is the center tap on a transformer used?
Provides capability of developing two high-voltage outputs.
6. Does a rectifier tube conduct on the positive or negative alternation of the input signal?
Positive.
7. What term is used to describe the period when the diode is not conducting?
Cutoff.
8. Current that flows in pulses in the same direction is called _____.
Pulsating dc.
9. For a diode to act as a rectifier, should it be connected in series or parallel with the load?
Series.
10. What is the Ripple frequency of a half-wave rectifier if the input frequency is 60 Hz?
60 hertz.
11. What is the equation for determining average voltage in a half-wave rectifier?
Eavg = 0.318 � Emax.
12. What is the ripple frequency of a full-wave rectifier with an input frequency of 60 Hz?
120 hertz.
13. What is the average voltage (Eavg) output of a full-wave rectifier that has an output of 100 volts peak?
63.6 volts.
14. What is the main disadvantage of the conventional full-wave rectifier?
The peak voltage is half that of a half-wave rectifier.
15. What main advantage does a bridge rectifier have over a conventional full-wave rectifier?
The bridge rectifier can produce double the voltage with the same size transformer.
16. If you increase the value of the capacitor will the XC increase or decrease? Why?
Decrease-Capacitance is inversely proportional to XC.
17. What is the most basic type of filter?
Capacitor.
18. In a capacitor filter, is the capacitor in series or parallel with the load?
Parallel.
19. Is better filtering achieved at a high frequency or at a low frequency at the input of the filter?
High.
20. Does a filter circuit increase or decrease the average output voltage?
Increase.
21. What determines the rate of discharge of the capacitor in a filter circuit?
Value of capacitance and load resistance.
22. Does low ripple voltage indicate good or bad filtering?
Good.
23. Is a full-wave rectifier output easier to filter than that of a half-wave rectifier?
Yes.
24. In an LC choke-input filter, what prevents the rapid charging of the capacitor?
Counter electro-motive force of the inductor.
25. What is the value usually chosen for a filter choke?
1 to 20 henries.
26. If the inductance of a choke-input filter is increased, will the output ripple voltage amplitude (Er) increase or decrease?
Decrease.
27. Is an RC filter used when a large current or a small current demand is required?
Small.
28. Why is the use of large value capacitors in filter circuits discouraged?
Expense.
29. When is a second RC filter stage used?
When ripple must be held at an absolute minimum.
30. What is the most commonly used filter in use today?
LC capacitor-input filter.
31. What are the two main disadvantages of an LC capacitor filter?
Cost of the inductor and size of the inductor.
32. What two factors can cause output dc voltage to change?
Ac line voltage and a change in load resistance.
33. What is the commonly used figure of merit for a power supply?
Percent of regulator.
34. If a power supply produces 20 volts with no load and 15 volts under full load, what is the percent of regulation?
33.33%
35. What percent of regulation would be ideal?
0%.
36. The purpose of a voltage regulator is to provide an output voltage with little or no ____.
Variation.
37. The two basic types of voltage regulators are _______ and _______.
Series and shunt.
38. When a series voltage regulator is used to control output voltages, any increase in the input voltage results in an increase/a decrease in the resistance of the regulating device.
Increase.
39. A shunt type voltage regulator is connected in series/parallel with the load resistance.
Parallel.
40. In an electron tube regulator, the electron tube replaces what component?
Variable resistor.
41. What is the purpose of the amperite regulator?
Current regulation.
42. As the tube filaments in the load heat up, will the circuit current increase or decrease?
Decrease.
43. What is the most important thing to remember when troubleshooting?
Safety precautions.
44. What is the main reason for grounding the return side of the transformer to the chassis?
Reduce the cost of manufacturing equipment.
45. What are two types of checks used in troubleshooting power supplies?
Visual and signal tracing.
 Author: CVN68 ID: 165452 Card Set: Neets Module 6 Assignment 3 Updated: 2012-08-09 20:27:27 Tags: Neets Folders: Description: Neets Show Answers: