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GMDSS · 605 questions

Element 3 - USCG Exam Questions

General radiotelephone operator knowledge: radio law and regulations, operating procedures, and radio equipment fundamentals.

Every question below is a real U.S. Coast Guard exam question with four choices. Answer one and the correct choice is revealed instantly, with the USCG reference and illustration where the question uses one.

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All Element 3 questions

Questions 101–200 of 605 · page 2 of 7

  1. #101 In rectangular coordinates, what is the impedance of a network composed of a 0.001-microfarad capacitor in series with a 400-ohm resistor, at 500 kHz?
  2. #102 What is the impedance of a network composed of a 100-picofarad capacitor in parallel with a 4000-ohm resistor, at 500 KHz? Specify your answer in pola...
  3. #103 In polar coordinates, what is the impedance of a network composed of a 100-ohm-reactance inductor in series with a 100-ohm resistor?
  4. #104 In polar coordinates, what is the impedance of a network composed of a 400-ohm-reactance capacitor in series with a 300-ohm resistor?
  5. #105 In polar coordinates, what is the impedance of a network composed of a 300-ohm-reactance capacitor, a 600-ohm-reactance inductor, and a 400-ohm resist...
  6. #106 In polar coordinates, what is the impedance of a network comprised of a 400-ohm-reactance inductor in parallel with a 300-ohm resistor?
  7. #107 Using the polar coordinate system, what visual representation would you get of a voltage in a sinewave circuit?
  8. #108 What is the magnitude of the impedance of a series AC circuit having a resistance of 6 ohms, an inductive reactance of 17 ohms, and zero capacitive re...
  9. #109 A 1-watt, 10-volt Zener diode with the following characteristics: Imin. = 5 mA; Imax. = 95 mA; and Z = 8 ohms, is to be used as part of a voltage regu...
  10. #110 Given a power supply with a no load voltage of 12 volts and a full load voltage of 10 volts, what is the percentage of voltage regulation?
  11. #111 What turns ratio does a transformer need in order to match a source impedance of 500 ohms to a load of 10 ohms?
  12. #112 Given a power supply with a full load voltage of 200 volts and a regulation of 25%, what is the no load voltage?
  13. #113 What is the conductance (G) of a circuit if 6 amperes of current flows when 12 volts DC is applied?
  14. #114 What happens to the conductivity of photoconductive material when light shines on it?
  15. #115 What is the photoconductive effect?
  16. #116 What does the photoconductive effect in crystalline solids produce a noticeable change in?
  17. #117 What is the description of an optoisolator?
  18. #118 What happens to the conductivity of a photosensitive semiconductor junction when it is illuminated?
  19. #119 What is the description of an optocoupler?
  20. #120 What factors determine the capacitance of a capacitor?
  21. #121 In Figure 3C4, if a small variable capacitor were installed in place of the dashed line, it would? illustration
  22. #122 In Figure 3C4, which component (labeled 1 through 4) is used to provide a signal ground? illustration
  23. #123 In Figure 3C5, which capacitor (labeled 1 through 4) is being used as a bypass capacitor? illustration
  24. #124 In Figure 3C5, the 1 µF capacitor is connected to a potentiometer that is used to: illustration
  25. #125 What is the purpose of a coupling capacitor?
  26. #126 A capacitor is sometimes placed in series with the primary of a power transformer to:
  27. #127 A transformer used to step up its input voltage must have:
  28. #128 A transformer primary of 2250 turns connected to 120 VAC will develop what voltage across a 500-turn secondary?
  29. #129 What is the ratio of the output frequency to the input frequency of a single-phase full-wave rectifier?
  30. #130 A power transformer has a single primary winding and three secondary windings producing 5.0 volts, 12.6 volts, and 150 volts. Assuming similar wire si...
  31. #131 A power transformer has a primary winding of 200 turns of #24 wire and a secondary winding consisting of 500 turns of the same size wire. When 20 volt...
  32. #132 In a linear electronic voltage regulator:
  33. #133 A switching electronic voltage regulator:
  34. #134 What device is usually used as a stable reference voltage in a linear voltage regulator?
  35. #135 In a regulated power supply, what type of component will most likely be used to establish a reference voltage?
  36. #136 A three-terminal regulator:
  37. #137 What is the range of voltage ratings available in Zener diodes?
  38. #138 How might two similar SCRs be connected to safely distribute the power load of a circuit?
  39. #139 What are the three terminals of an SCR?
  40. #140 Which of the following devices acts as two SCRs connected back to back, but facing in opposite directions and sharing a common gate?
  41. #141 What is the transistor called that is fabricated as two complementary SCRs in parallel with a common gate terminal?
  42. #142 What are the three terminals of a TRIAC?
  43. #143 What circuit might contain a SCR?
  44. #144 What is one common use for PIN diodes?
  45. #145 What is a common use of a hot-carrier diode?
  46. #146 Structurally, what are the two main categories of semiconductor diodes?
  47. #147 What special type of diode is capable of both amplification and oscillation?
  48. #148 What type of semiconductor diode varies its internal capacitance as the voltage applied to its terminals varies?
  49. #149 What is the principal characteristic of a tunnel diode?
  50. #150 What is the meaning of the term alpha" with regard to bipolar transistors? The change of:"
  51. #151 What are the three terminals of a bipolar transistor?
  52. #152 What is the meaning of the term beta" with regard to bipolar transistors? The change of:"
  53. #153 What are the elements of a unijunction transistor?
  54. #154 The beta cutoff frequency of a bipolar transistor is the frequency at which:
  55. #155 What does it mean for a transistor to be fully saturated?
  56. #156 A common base amplifier has:
  57. #157 What does it mean for a transistor to be cut off?
  58. #158 An emitter-follower amplifier has:
  59. #159 What conditions exists when a transistor is operating in saturation?
  60. #160 For current to flow in an NPN silicon transistor's emitter-collector junction, the base must be:
  61. #161 When an NPN transistor is operating as a Class A amplifier, the base-emitter junction:
  62. #162 What type of bias is required for an LED to produce luminescence?
  63. #163 What determines the visible color radiated by an LED junction?
  64. #164 What is the approximate operating current of a light-emitting diode?
  65. #165 What would be the maximum current to safely illuminate a LED?
  66. #166 An LED facing a photodiode in a light-tight enclosure is commonly known as a/an:
  67. #167 What circuit component must be connected in series to protect an LED?
  68. #168 What describes a diode junction that is forward biased?
  69. #169 Why are special precautions necessary in handling FET and CMOS devices?
  70. #170 What do the initials CMOS stand for?
  71. #171 What is the piezoelectric effect?
  72. #172 An electrical relay is a:
  73. #173 In which oscillator circuit would you find a quartz crystal?
  74. #174 What is the approximate magnitude of the impedance of a parallel R-L-C circuit at resonance?
  75. #175 What is the approximate magnitude of the impedance of a series R-L-C circuit at resonance?
  76. #176 How could voltage be greater across reactances in series than the applied voltage?
  77. #177 What is the characteristic of the current flow in a series R-L-C circuit at resonance?
  78. #178 What is the characteristic of the current flow within the parallel elements in a parallel R-L-C circuit at resonance?
  79. #179 What is the relationship between current through a resonant circuit and the voltage across the circuit?
  80. #180 What is the main advantage of using an op-amp audio filter over a passive LC audio filter?
  81. #181 What are the characteristics of an inverting operational amplifier (op-amp) circuit?
  82. #182 Gain of a closed-loop op-amp circuit is determined by?
  83. #183 Where is the external feedback network connected to control the gain of a closed-loop op-amp circuit?
  84. #184 Which of the following op-amp circuits is operated open-loop?
  85. #185 In the op-amp oscillator circuit shown in Figure 3D6, what would be the most noticeable effect if the capacitance of C were suddenly doubled? illustration
  86. #186 What frequency synthesizer circuit uses a phase comparator, look-up table, digital-to-analog converter, and a low-pass antialias filter?
  87. #187 A circuit that compares the output of a voltage-controlled oscillator (VCO) to a frequency standard and produces an error voltage that is then used to...
  88. #188 RF input to a mixer is 200 MHz and the local oscillator frequency is 150 MHz. What output would you expect to see at the IF output prior to any filter...
  89. #189 What spectral impurity components might be generated by a phase-locked-loop synthesizer?
  90. #190 In a direct digital synthesizer, what are the unwanted components on its output?
  91. #191 What is the definition of a phase-locked loop (PLL) circuit?
  92. #192 Given the combined DC input voltages, what would the output voltage be in the circuit shown in Figure 3D7? illustration
  93. #193 Which lamps would be lit in the circuit shown in Figure 3D8? illustration
  94. #194 What will occur if an amplifier input signal coupling capacitor fails open?
  95. #195 In Figure 3D9, determine if there is a problem with this regulated power supply and identify the problem. illustration
  96. #196 In Figure 3D10 with a square wave input what would be the output? illustration
  97. #197 With a pure AC signal input to the circuit shown in Figure 3D11, what output wave form would you expect to see on an oscilloscope display? illustration
  98. #198 What is the voltage range considered to be valid logic low input in a TTL device operating at 5 volts?
  99. #199 What is the voltage range considered to be a valid logic high input in a TTL device operating at 5.0 volts?
  100. #200 What is the common power supply voltage for TTL series integrated circuits?

Element 3 questions: what to expect

Q How many Element 3 questions are in the GMDSS pool?

There are 605 Element 3 questions on this site, every one released by the U.S. Coast Guard or taken from the National Maritime Center's sample examinations, with its correct answer. The exam draws its Element 3 module from the same pool.

Q What score do I need to pass the Element 3 module?

Most USCG exam modules, including Element 3, require 70 percent to pass. Rules of the Road modules require 90 percent.

Q Are these the real USCG Element 3 exam questions?

Yes. They are the published U.S. Coast Guard questions, matched to the National Maritime Center's 2026 sample examinations. Answer any question to see the correct choice, the USCG reference and the illustration where the question uses one.

About the GMDSS question pool

These are the published GMDSS Element 3 questions covering general radiotelephone operator knowledge: radio law, operating procedures, and equipment fundamentals.