Download ELT2010 Student Workbook

ELT2010 Electro-Assembly 2
Student Workbook
Complete the following questions in the space and manner requested.
Resistors – Complete the following questions after reading Chapter 10
1. Explain the function of a resistor in a circuit.
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2. What are three ways resistors are rated?
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3. What is a common use for resistance wire?
4. ______________________ resistors are typically used in circuits that carry high currents.
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5. Name the two different types of resistors and explain how they are different.
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6. How are resistors identified?
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7. Many resistors have their electrical resistance shown by a set of color codes, or ”bands,” imprinted
around their circumference. A standard color code associates each color with a specific decimal digit
(0 through 9). Associate each of the following digits with its respective color:
0=
1=
2=
3=
4=
5=
6=
7=
8=
9=
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Student Workbook
8. Determine the nominal resistance values of these resistors, given their band colors, and also express
the allowable tolerance in ohms. For example, a 25 k resistor with a 10% tolerance rating would
have an allowable tolerance of +/- 2.5 k.
• Red, Org, Blu, Gld =
• Brn, Blk, Grn, Sil =
• Blu, Blk, Brn, Gld =
• Yel, Vio, Red, Sil =
• Grn, Brn, Yel =
• Wht, Blu, Blk, Sil =
• Gry, Grn, Org, Gld =
• Org, Org, Gld =
• Vio, Red, Sil, Gld =
• Brn, Red, Blk, Sil =
9. Determine whether or not the following resistors measure within the resistance range specified by
theircolor codes:
• (Org, Org, Red, Blk, Blu) Measured resistance = 332.5
• (Brn, Blk, Blk, Gld, Red) Measured resistance = 9.7
• (Blu, Vio, Brn, Red, Grn) Measured resistance = 67.43 k
• (Red, Wht, Grn, Yel, Vio) Measured resistance = 2.949 M
• (Yel, Vio, Org, Gld) Measured resistance = 44.68 k
• (Gry, Red, Brn, Sil) Measured resistance = 905
• (Grn, Blu, Gld) Measured resistance = 6.73
• (Vio, Brn, Red, Gld, Brn) Measured resistance = 70.82
• (Wht, Org, Blu, Brn, Grn) Measured resistance = 9.38 k
• (Red, Blk, Wht, Grn, Vio) Measured resistance = 20.86 M
Assume that all five-band resistors listed here use the precision color code as opposed to the
military 5-band code where the fifth band indicates resistor reliability.
10. Find two real resistors and bring them with you to class for discussion. Identify as much
information as you can about your resistors prior to discussion:
• Resistance (ideal)
• Resistance (actual)
• Power rating
• Type (carbon composition, metal film, wire-wound, etc.)
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Student Workbook
11. When a resistor conducts electric current, its temperature increases. Explain how this phenomenon
is significant to the application of resistors in electric circuits. In other words, why would we care
about a resistor’s temperature increasing? Also, what does this indicate about the technical ratings
of resistors? Aside from having a specific resistance rating (i.e. a certain number of ohms), what
other rating is important for proper selection of resistors in electric circuits?
12. What does the last color band represent on a color-coded resistor?
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Diodes (Refer to the video clip on diodes and chapter 35 in your textbook)
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13. What is the most common semiconducting material used in making electronic components?
14. A diode’s ability to turn AC current into DC current is called _____________________________.
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15. State three ways in which diodes are commonly rated?
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16. A diode is testing using an ohmmeter. What readings would indicate that the diode is not defective?
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17. What is the purpose of a rectifier diode?
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Student Workbook
18. What is the purpose of a circuit control diode?
19. What is an LED specifically designed to do?
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20. How is an infrared-emitting diode different from a conventional light-emitting diode?
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21.
Under what conditions is a photodiode designed to conduct electricity?
Capacitors (refer to the video clip on capacitors and chapter 30 in your text)
22. What is capacitance?
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23. How is energy stored and released in a capacitor?
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24. Describe the potential hazard involved in the use of high-voltage capacitors in dc circuits.
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25. What unit is used to measure capacitance?
26. What are capacitors rated for in addition to capacitance?
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27. How would two 50 µF capacitors be connected to provide a total capacitance of 100 µF?
28. What is the main advantage of polarized capacitors?
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29.
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When connecting polarized capacitors into dc circuits, what polarity rule is followed?
ELT2010 Electro-Assembly 2
Student Workbook
Transistors (refer to the video on transistors and chapter 37 in your textbook)
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30. Give three ways in which transistors are used.
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31. What are the two main families of transistors?
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32. What is the basic difference between the connection of an NPN and PNP bipolar-junctiontransistor
(BJT)?
Integrated Circuits (refer to the video on integrated circuits and chapter 40 in your text)
33. What is normally contained within a single IC chip?
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34. List four common electronic component parts that can be formed on an IC chip.
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35. List three major advantages that ICs have over conventional discrete-type circuits.
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36. State two major limitations of ICs.
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37. Why is no attempt usually made to reproduces the internal circuit schemataic of an IC chip on
diagrams?
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Student Workbook
38. List four important things to observe when working with IC circuits.
39. Outline the basic steps involved in troubleshooting an IC package chip.
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Inductors (refer to the video on inductors and chapter 30 in your text)
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40. Name three basic types of inductors.
41. How is energy stored and released in an inductor?
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42. Define the term inductance.
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43. List four factors that determine the inductance of a coil.
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Transducers (refer to chapter 32 in your text)
44. What are the two basic functions of electric transducers?
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45. How is electric energy converted into mechanical energy in a permanent-magnet speaker?
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46. How is mechanical energy converted into electric energy in a permanent-magnet speaker?
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Student Workbook
47. State the type of electric-output signal produced by each of the following microphones:
carbon microphone
dynamic microphone
crystal microphone
capacitor or condenser microphone
48. Why would a headphone, rather than a speaker, be used in testing the weak ac signal voltage
produced by a dynamic microphone?
49. How is energy converted in a crystal phonograph cartridge?
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50. Explain how a computer disk drive writes and reads data.
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51. How is digital data recorded on the surface of an optical disk?
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52. How is this information retrieved by the compact disk player?
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Printed Circuit Boards (refer to the video on circuit board etching and chapter 33 in your text)
53. List three advantages that a PC board has over the traditional hand-wired type of chassis.
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54. Describe the construction of a single-sided PC board.
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55. On what side of the board are the components mounted?
56. How are the circuit connections made?
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ELT2010 Electro-Assembly 2
Student Workbook
57. State the function of the resist and etchant as used in processing a PC board.
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58. List the basic steps involved in the processing of a PC board using the photographic-printing method.
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59. When is it a definite advantage to use the print-and-etch method rather than the photographicprinting process?
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60. What must you be careful of when drilling lead-access holes in a PC board?
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61. Why must the copper foil of a PC board be cleaned before the soldering is started?
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62. Explain how axial-lead components are mounted to the PC board.
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63. In what way is surface-mount technology different from conventional mounting methods?
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64. What is the purpose of flux in the soldering process?
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65. What type of flux should not be used for PC board soldering?
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66. After soldering, why should flux residue be removed?
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ELT2010 Electro-Assembly 2
Student Workbook
67. What type and diameter of solder is suitable for most PC board soldering?
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68. What soldering iron power range is recommended for use with PC board soldering?
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69. When should the tip of the soldering iron be cleaned?
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70. What damage can be done by leaving the soldering iron on the connection for too long a period of
time?
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71. Name two visual indications of a well-soldered connection.
72. Name two methods for removing solder from printed-circuit boards.
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73. When access to the bottom of a PC board is restricted, how can emergency repairs be made?
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74. What is a heat-sink tool used for?
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75. Describe the procedure for repairing a break in a PC foil.
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ELT2010 Electro-Assembly 2
Student Workbook
Circuit Construction
The final project in this module is actually creating a project using a printed circuit board, components,
as well as test and soldering equipment. Your teacher will provide you with a project kit containing
the PC board, components, schematic and instructions. The first step will be to build the circuit using
a breadboard. This will allow you to determine if the components are functioning and perform as
you expect them to.
Take your completed breadboard circuit to your instructor and complete the electronic project rubric.
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Next, work slowly and carefully while assembling your circuit. Refer to past information on soldering and
soldering components before beginning.
Take your completed soldered circuit to your instructor and complete the electronic project rubric.
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If there is time, your teacher may allow you to complete another project, or build one from existing
salvaged components.
Take your completed circuit to your instructor and complete the electronic project rubric.
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