1. Technician License Course Chapter 3 Electricity, Components and Circuits Lesson Plan Module 6

2. Electronics – Controlling the Flow of Current To make an electronic device (like a radio) do something useful (like receive a signal), we need to control and manipulate the flow of current. There are a number of different electronic components that we use to do this.

3. The Resistor The function of the resistor is to restrict (limit) the flow of current through it. Electrical energy is converted to heat. Circuit Symbol Measured in Ohms

4. Resistors Fixed resistors are the most common. Adjustable resistors can be tapped at various resistances. Potentiometers are used for audio volume controls. Rated in watts they can safely pass.

5. Various Resistors

6. The Capacitor The function of the capacitor is to temporarily store electric current. –Like a very temporary storage battery. –Stores energy in an electrostatic field. –Blocks DC, Passes AC Circuit Symbol Measured in Farads

7. Capacitor Types Fixed Non-Polarized Electrolytic Variable

8. The Inductor The function of the inductor is to temporarily store electric current. –Is basically a coil of wire. –Stores energy in a magnetic field. –Resists changes in current. Circuit Symbol Measured in Henrys

9. Inductors

10. Reactance Electrical current interacts with both capacitors and inductors. This interaction is called reactance, and varies with frequency. Capacitors store energy in an electrostatic field. Capacitors oppose changes in voltage. Inductors store energy in a magnetic field. Inductors oppose changes in current. Reactance is measured in ohms.

11. Resonance Because capacitors and inductors store energy in different ways, the stored energy can actually cancel each other under the right conditions (at a particular frequency). –Capacitors – electric field –Inductors – magnetic field Cancelled current = no reactance, just leaving resistance.

12. Resonant Antenna If an antenna is designed correctly, the capacitive reactance cancels the inductive reactance. Theoretically, the resulting reactance is zero. –Leaving only resistance – meaning minimum impediment to the radio frequency currents flowing in the antenna and sending the radio wave into space.

13. Antennas are Part Capacitor – Part Inductor – Part Resistor Antennas actually have characteristics of capacitor, inductor and resistor electronic components. Capacitors and inductors, because they store energy in fields, react differently to ac than dc. –Special kind of resistance to the flow of ac – called reactance.

14. The Diode Diodes permit electrical flow in only one direction. –Anode is positive –Cathode is negative Cathode end usually has a stripe for identification.

15. Diode Types LED’s emit light when voltage is applied. (Light Emitting Diode) Rectifiers convert AC to pulsing DC. Zener and Schottky are special purpose diodes.

16. Rectification

17. The Transistor The function of the transistor is to variably control the flow of current. –Much like an electronically controlled valve. –An analogy, the faucet in your sink. Circuit Symbol (Bipolar Transistors) NPN PNP

18. The Transistor Bipolar transistors are constructed with three alternating layers of semiconductor material. The connections are the emitter, the collector and the base. How much signal amplification is present is the gain of the device. Circuit Symbol (Bipolar Transistors) NPN PNP

19. Transistor Types

20. The Integrated Circuit The integrated circuit is a collection of components contained in one device that accomplishes a specific task. Transistors, diodes, capacitors, inductors, resistors. –Acts like a “black-box” Circuit Symbol

21. Protective Components – Intentional Open Circuits Fuses and circuit breakers are designed to interrupt the flow of current if the current becomes uncontrolled. –Fuses blow – one time protection. –Circuit breakers trip – can be reset and reused. Circuit Symbols

22. Protective Components Never replace a fuse or circuit breaker with another that has a higher amperage rating. You could damage the equipment or cause a fire. Use the same amperage and voltage rating. Circuit Symbols

23. Control Devices Switches –On / Off –Poles Single Double –Throw Relays – electrically controlled switches

24. Other Circuit Symbols

25. Putting It All Together in a Circuit Diagram

26. What is the ability to store energy in an electric field called? (T5C01) A. Inductance B. Resistance C. Tolerance D. Capacitance

27. What is the ability to store energy in an electric field called? (T5C01) A. Inductance B. Resistance C. Tolerance D. Capacitance

28. What is the basic unit of capacitance? (T5C02) A. The farad B. The ohm C. The volt D. The henry

29. What is the basic unit of capacitance? (T5C02) A. The farad B. The ohm C. The volt D. The henry

30. What is the ability to store energy in a magnetic field called? (T5C03) A. Admittance B. Capacitance C. Resistance D. Inductance

31. What is the ability to store energy in a magnetic field called? (T5C03) A. Admittance B. Capacitance C. Resistance D. Inductance

32. What is the basic unit of inductance? (T5C04) A. The coulomb B. The farad C. The henry D. The ohm

33. What is the basic unit of inductance? (T5C04) A. The coulomb B. The farad C. The henry D. The ohm

34. What electrical component is used to oppose the flow of current in a DC circuit? (T6A01) A. Inductor B. Resistor C. Voltmeter D. Transformer

35. What electrical component is used to oppose the flow of current in a DC circuit? (T6A01) A. Inductor B. Resistor C. Voltmeter D. Transformer

36. What type of component is often used as an adjustable volume control? (T6A02) A. Fixed resistor B. Power resistor C. Potentiometer D. Transformer

37. What type of component is often used as an adjustable volume control? (T6A02) A. Fixed resistor B. Power resistor C. Potentiometer D. Transformer

38. What electrical parameter is controlled by a potentiometer? (T6A03) A. Inductance B. Resistance C. Capacitance D. Field strength

39. What electrical parameter is controlled by a potentiometer? (T6A03) A. Inductance B. Resistance C. Capacitance D. Field strength

40. What electrical component stores energy in an electric field? (T6A04) A. Resistor B. Capacitor C. Inductor D. Diode

41. What electrical component stores energy in an electric field? (T6A04) A. Resistor B. Capacitor C. Inductor D. Diode

42. What type of electrical component consists of two or more conductive surfaces separated by an insulator? (T6A05) A. Resistor B. Potentiometer C. Oscillator D. Capacitor

43. What type of electrical component consists of two or more conductive surfaces separated by an insulator? (T6A05) A. Resistor B. Potentiometer C. Oscillator D. Capacitor

44. What type of electrical component stores energy in a magnetic field? (T6A06) A. Resistor B. Capacitor C. Inductor D. Diode

45. What type of electrical component stores energy in a magnetic field? (T6A06) A. Resistor B. Capacitor C. Inductor D. Diode

46. What electrical component is usually composed of a coil of wire? (T6A07) A. Switch B. Capacitor C. Diode D. Inductor

47. What electrical component is usually composed of a coil of wire? (T6A07) A. Switch B. Capacitor C. Diode D. Inductor

48. What electrical component is used to connect or disconnect electrical circuits? (T6A08) A. Zener diode B. Switch C. Inductor D. Variable resistor

49. What electrical component is used to connect or disconnect electrical circuits? (T6A08) A. Zener diode B. Switch C. Inductor D. Variable resistor

50. What electrical component is used to protect other circuit components from current overloads? (T6A09) A. Fuse B. Capacitor C. Shield D. Inductor

51. What electrical component is used to protect other circuit components from current overloads? (T6A09) A. Fuse B. Capacitor C. Shield D. Inductor

52. What class of electronic components is capable of using a voltage or current signal to control current flow? (T6B01) A. Capacitors B. Inductors C. Resistors D. Transistors

53. What class of electronic components is capable of using a voltage or current signal to control current flow? (T6B01) A. Capacitors B. Inductors C. Resistors D. Transistors

54. What electronic component allows current to flow in only one direction? (T6B02) A. Resistor B. Fuse C. Diode D. Driven element

55. What electronic component allows current to flow in only one direction? (T6B02) A. Resistor B. Fuse C. Diode D. Driven element

56. Which of these components can be used as an electronic switch or amplifier? (T6B03) A. Oscillator B. Potentiometer C. Transistor D. Voltmeter

57. Which of these components can be used as an electronic switch or amplifier? (T6B03) A. Oscillator B. Potentiometer C. Transistor D. Voltmeter

58. Which of these components is made of three layers of semiconductor material? (T6B04) A. Alternator B. Bipolar junction transistor C. Triode D. Pentagrid converter

59. Which of these components is made of three layers of semiconductor material? (T6B04) A. Alternator B. Bipolar junction transistor C. Triode D. Pentagrid converter

60. Which of the following electronic components can amplify signals? (T6B05) A. Transistor B. Variable resistor C. Electrolytic capacitor D. Multi-cell battery

61. Which of the following electronic components can amplify signals? (T6B05) A. Transistor B. Variable resistor C. Electrolytic capacitor D. Multi-cell battery

62. How is a semiconductor diode’s cathode lead usually identified? (T6B06) A. With the word “cathode” B. With a stripe C. With the letter “C” D. All of these choices are correct

63. How is a semiconductor diode’s cathode lead usually identified? (T6B06) A. With the word “cathode” B. With a stripe C. With the letter “C” D. All of these choices are correct

64. What does the abbreviation “LED” stand for? (T6B07) A. Low Emission Diode B. Light Emitting Diode C. Liquid Emission Detector D. Long Echo Delay

65. What does the abbreviation “LED” stand for? (T6B07) A. Low Emission Diode B. Light Emitting Diode C. Liquid Emission Detector D. Long Echo Delay

66. What does the abbreviation “FET” stand for? (T6B08) A. Field Effect Transistor B. Fast Electron Transistor C. Free Electron Transition D. Field Emission Thickness

67. What does the abbreviation “FET” stand for? (T6B08) A. Field Effect Transistor B. Fast Electron Transistor C. Free Electron Transition D. Field Emission Thickness

68. What are the names of the two electrodes of a diode? (T6B09) A. Plus and minus B. Source and drain C. Anode and cathode D. Gate and base

69. What are the names of the two electrodes of a diode? (T6B09) A. Plus and minus B. Source and drain C. Anode and cathode D. Gate and base

70. Which semiconductor component has an emitter electrode? (T6B10) A. Bipolar transistor B. Field effect transistor C. Silicon diode D. Bridge rectifier

71. Which semiconductor component has an emitter electrode? (T6B10) A. Bipolar transistor B. Field effect transistor C. Silicon diode D. Bridge rectifier

72. Which semiconductor component has a gate electrode? (T6B11) A. Bipolar transistor B. Field effect transistor C. Silicon diode D. Bridge rectifier

73. Which semiconductor component has a gate electrode? (T6B11) A. Bipolar transistor B. Field effect transistor C. Silicon diode D. Bridge rectifier

74. What is the term that describes a transistor’s ability to amplify a signal? (T6B12) A. Gain B. Forward resistance C. Forward voltage drop D. On resistance

75. What is the term that describes a transistor’s ability to amplify a signal? (T6B12) A. Gain B. Forward resistance C. Forward voltage drop D. On resistance

76. What is the name for standardized representations of components in an electrical wiring diagram? (T6C01) A. Electrical depictions B. Grey sketch C. Schematic symbols D. Component callouts

77. What is the name for standardized representations of components in an electrical wiring diagram? (T6C01) A. Electrical depictions B. Grey sketch C. Schematic symbols D. Component callouts

78. Which of the following is accurately represented in electrical circuit schematic diagrams? (T6C13) A. Wire lengths B. Physical appearance of components C. The way components are interconnected D. All of these choices are correct

79. Which of the following is accurately represented in electrical circuit schematic diagrams? (T6C13) A. Wire lengths B. Physical appearance of components C. The way components are interconnected D. All of these choices are correct

80. Which of the following devices or circuits changes an alternating current into a varying direct current signal? (T6D01) A. Transformer B. Rectifier C. Amplifier D. Reflector

81. Which of the following devices or circuits changes an alternating current into a varying direct current signal? (T6D01) A. Transformer B. Rectifier C. Amplifier D. Reflector

82. Which best describes a relay? (T6D02) A. A switch controlled by an electromagnet B. A current controlled amplifier C. An optical sensor D. A pass transistor

83. Which best describes a relay? (T6D02) A. A switch controlled by an electromagnet B. A current controlled amplifier C. An optical sensor D. A pass transistor

84. Which of the following can be used to display signal strength on a numeric scale? (T6D04) A. Potentiometer B. Transistor C. Meter D. Relay

85. Which of the following can be used to display signal strength on a numeric scale? (T6D04) A. Potentiometer B. Transistor C. Meter D. Relay

86. What component is commonly used to change 120V AC house current to a lower AC voltage for other uses? (T6D06) A. Variable capacitor B. Transformer C. Transistor D. Diode

87. What component is commonly used to change 120V AC house current to a lower AC voltage for other uses? (T6D06) A. Variable capacitor B. Transformer C. Transistor D. Diode

88. Which of the following is commonly used as a visual indicator? (T6D07) A. LED B. FET C. Zener diode D. Bipolar transistor

89. Which of the following is commonly used as a visual indicator? (T6D07) A. LED B. FET C. Zener diode D. Bipolar transistor

90. Which of the following is used together with an inductor to make a tuned circuit? (T6D08) A. Resistor B. Zener diode C. Potentiometer D. Capacitor

91. Which of the following is used together with an inductor to make a tuned circuit? (T6D08) A. Resistor B. Zener diode C. Potentiometer D. Capacitor

92. What is the name of the device that combines several semiconductors and other components into one package? (T6D09) A. Transducer B. Multi-pole relay C. Integrated circuit D. Transformer

93. What is the name of the device that combines several semiconductors and other components into one package? (T6D09) A. Transducer B. Multi-pole relay C. Integrated circuit D. Transformer

94. What is the purpose of a fuse in an electrical circuit? (T0A04) A. To prevent power supply ripple from damaging a circuit B. To interrupt power in case of overload C. To limit current to prevent shocks D. All of these choices are correct

95. What is the purpose of a fuse in an electrical circuit? (T0A04) A. To prevent power supply ripple from damaging a circuit B. To interrupt power in case of overload C. To limit current to prevent shocks D. All of these choices are correct

96. Why is it unwise to install a 20-ampere fuse in the place of a 5 ampere fuse? (T0A05) A. The larger fuse would be likely to blow because it is rated for higher current B. The power supply ripple would greatly increase C. Excessive current could cause a fire D. All of these choices are correct

97. Why is it unwise to install a 20-ampere fuse in the place of a 5 ampere fuse? (T0A05) A. The larger fuse would be likely to blow because it is rated for higher current B. The power supply ripple would greatly increase C. Excessive current could cause a fire D. All of these choices are correct