Neets Module 7 Assignment 4

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Neets Module 7 Assignment 4
2012-08-09 16:30:23

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  1. What are the four basic sections of a power supply?
    • Transformer
    • Rectifier
    • Filter
    • Regulator.
  2. What is the purpose of the rectifier section?
    To change ac to pulsating dc.
  3. What is the purpose of the filter section?
    To change pulsating dc to pure dc.
  4. What is the purpose of the regulator section?
    To maintain a constant voltage to the load.
  5. What is the name of the simplest type of rectifier which uses one diode?
    The half-wave rectifier.
  6. If the output of a half-wave rectifier is 50-volts peak, what is the average voltage?
    15.9 volts.
  7. In addition to stepping up or stepping down the input line voltage, what additional purpose does the transformer serve?
    It isolates the chassis from the power line.
  8. What was the major factor that led to the development of the full-wave rectifier?
    The fact that the full-wave rectifier uses the full output, both half cycles, of the transformer.
  9. What is the ripple frequency of a full-wave rectifier with an input frequency of 60 Hz?
    120 hertz.
  10. What is the average voltage (Eavg) Output of a full-wave rectifier with an output of 100 volts peak?
    63.7 volts.
  11. What is the main disadvantage of a conventional full-wave rectifier?
    Peak voltage is half that of the half-wave rectifier.
  12. What main advantage does a bridge rectifier have over a conventional full-wave rectifier?
    The bridge rectifier can produce twice the voltage with the same size transformer.
  13. If you increase the value of the capacitor, will the XC increase or decrease? Why?
    It will decrease. Capacitance is inversely proportional to XC.
  14. What is the most basic type of filter?
    The capacitor filter.
  15. In a capacitor filter, is the capacitor in series or in parallel with the load?
  16. Is filtering better at a high frequency or at a low frequency?
    At a high frequency.
  17. Does a filter circuit increase or decrease the average output voltage?
    A filter circuit increases the average output voltage.
  18. What determines the rate of discharge of the capacitor in a filter circuit?
    Value of capacitance and load resistance.
  19. Does low ripple voltage indicate good or bad filtering?
  20. Is a full-wave rectifier output easier to filter than that of a half-wave rectifier?
  21. In an LC choke-input filter, what prevents the rapid charging of the capacitor?
    The CEMF of the inductor.
  22. What is the range of values usually chosen for a choke?
    From 1 to 20 henries.
  23. If the impedance of the choke is increased, will the ripple amplitude increase or decrease?
  24. Why is the use of large value capacitors in filter circuits discouraged?
  25. When is a second RC filter stage used?
    When ripple must be held at an absolute minimum.
  26. What is the most commonly used filter today?
    LC capacitor-input filter.
  27. What are the two main disadvantages of an LC capacitor filter?
    Cost and size of the inductor.
  28. Circuits which maintain constant voltage or current outputs are called dc voltage or dc current ___.
  29. The purpose of a voltage regulator is to provide an output voltage with little or no ___.
  30. The two basic types of voltage regulators are ___ and ___.
    Series and shunt.
  31. When a series voltage regulator is used to control output voltages, any increase in the input voltage results in an increase/a decrease (which one) in the resistance of the regulating device.
    An increase.
  32. A shunt-type voltage regulator is connected in serial/parallel (which one) with the load resistance.
    In parallel.
  33. A half-wave voltage doubler is made up of how many half-wave rectifiers?
  34. If a half-wave rectifier is added to a half-wave voltage doubler, the resulting circuit is a voltage ____.
  35. In a full-wave voltage doubler, are the capacitors connected in series or in parallel with the output load?
    In parallel.
  36. What is the most important thing to remember when troubleshooting?
    Safety precautions.
  37. What is the main reason for grounding the return side of the transformer to the chassis?
    To eliminate shock hazard.
  38. What are two types of checks used in troubleshooting power supplies?
    Visual and signal tracing.