PinoyBIX Engineering Problem Solving and Reference

This is 100 items set of Practice Examination 12 in Electronics Engineering composed of previous and/or poterntial Board Exams Questions. Read each questions and choices carefully! Choose the best answer. In the actual board, you have to answer 100 items in Electronics Engineering within 5 hours. You have to get at least 70% to pass the subject. Electronics Engineering is 30% of the total 100% Board Rating along with Mathematics (20%), General Engineering and Applied Sciences (20%) and Electronics Systems and Technology (30%).

Start the Test Yourself Exam 12

Choose the letter of the best answer in each questions.

1. An advantage of an electromagnet over a permanent magnet is that:

• A. An electromagnet can be switched on and off
• B. An electromagnet does not have specific polarity
• C. An electromagnet requires no power source
• D. Permanent magnets must always be cylindrical

ANS: A

2. The quantity of magnetism retained by a magnetic material after withdrawal of the magnetized force is called

• A. Leftover magnetism
• B. Residual magnetism
• C. Hysteresis
• D. Coercivity

ANS: B

3. Three resistors of 10, 15, and 20 Ω each are connected in parallel. What is the total conductance?

• A. 0.217 S
• B. 3.41 S
• C. 4.62 S
• D. 0.52 S

ANS: A

4. What temperature in which the specific resistance of materials is usually measured?

• A. 290 K
• B. 300 K
• C. 20°C
• D. 0°C

ANS: C

5. When one resistance in a series string is open, the

• A. current is maximum in the normal resistances
• B. current is zero in all of the resistances
• C. voltage is zero across the open resistance
• D. current increases in the voltage source

ANS: B

6. The equivalent wye element of 3 equal resistors each equal to R and connected in delta is

• A. R
• B. 3R/2
• C. R/3
• D. 3R

ANS: C

7. A lead storage battery is rated at 12 V. If the internal resistance is 0.01 Ω, what is the maximum power that can be delivered to the load?

• A. 1,200 W
• B. 7,200 W
• C. 3,600 W
• D. 1,800 W

ANS: C

8. A simple circuit having a source of 7 nanovolts and a load of 3 kilo-mega ohms has a current equivalent to

• A. 23.33 amperes
• B. 2.333 attoamperes
• C. 2.333 amperes
• D. 2.333 deca amperes

ANS: B

9. What happens to the flow of electrons in electronic circuit when the resistance is increased?

• A. The speed of flow will remain constant
• B. The flow become faster
• C. The flow will be decreased
• D. No flow will occur

ANS: C

10. A circuit contains an inductor of 10 H in series with the capacitor of 0.001 F and operating at a frequency of 4 MHz. What is the net reactance or X in MΩ?

• A. 2.4727
• B. 2472.7
• C. 247.27
• D. 24.727

ANS: D

11. What is the relationship between frequency and the value of R?

• A. R varies indirectly
• B. R varies indirectly
• C. Frequency has no effect
• D. R varies directly

ANS: C

12. Longest life cell capable of 20, 000 times charged-discharged cycle and could last 30 years or over

• A. Nickel-cadmium cell
• B. Lithium cell
• C. Nickel hydrogen
• D. Alkaline cell

ANS: C

13. It is considered to be a negative charge of electricity?

• A. Atom
• B. Electron
• C. Neutron
• D. Proton

ANS: B

14. Refers to a field surrounding electrons and protons at stationary period indicating a stored energy

• A. Magnetic field
• B. Electrostatic field
• C. Electron field
• D. Electrodynamic field

ANS: B

15. The time required to complete one complete cycle of a waveform

• A. Crest
• B. Wavelength
• C. Frequency
• D. Period

ANS: D

16. Lines of flux generated by one winding which do not link the other winding

• A. Flux loss
• B. Leakage flux
• C. Reactance leakage
• D. Inductance leakage

ANS: A

17. What determines whether a substance is an insulator or a conductor?

• A. Number of protons
• B. Number of Photons
• C. Number of valence electrons
• D. Number of neutrons

ANS: C

18. Which of the following is positive electricity?

• A. Resinous dynamic electricity
• B. Vitreous dynamic electricity
• C. Vitreous static electricity
• D. Resinous static electricity

ANS: C

19. If the magnitude of the potential difference is generated by a single conductor passing through a magnetic field, which of the following statements is FALSE?

• A. The potential difference depends on the speed with which the conductor cuts the magnetic field
• B. The potential difference depends on the length of the conductor that cuts the magnetic field
• C. The potential difference depends on the magnetic field density that is present
• D. The potential difference depends on the diameter of the conductor that cuts the magnetic field

ANS: D

20. A current of 10-A flows through a 1 mm diameter wire. What is the average number of electrons that pass through a cross section of the wire per second?

• A. 1.6 x 10¹⁸ e/s
• B. 6.2 x 10¹⁸ e/s
• C. 1.6 x 10¹⁹ e/s
• D. 6.3 x 10¹⁹ e/s

ANS: D

21. Which of the following statements is true for steady-state conditions in a circuit powered by a dry a cell?

• A. Voltage is dependent upon time
• B. Capacitors behave as short circuits
• C. Inductors behave as short circuits
• D. Resistors behave as open circuits

ANS: C

22. What is the internal resistance of a 9 V battery that delivers 100 A when its terminals are shorted?

• A. 0.09 Ω
• B. 11 Ω
• C. 1.0 Ω
• D. 90 Ω

ANS: A

23. The change in the direction of a compass needle, when a current-carrying wire is brought near, is:

• A. Electromagnetic deflection
• B. Electrostatic force
• C. Magnetic force
• D. Electroscopic force

ANS: A

24. Suppose a certain current in a galvanometer causes the needle to deflect 20 degrees, and then this current is doubled. The needle deflection:

• A. Will decrease
• B. Will stay the same
• C. Will increase
• D. Will reverse direction

ANS: C

25. A unidirectional form of DC can be derived from which of the following sources?

• A. Battery
• B. Generator
• C. Rectifier circuits
• D. Power supply

ANS: B

26. 2.4 V of DC voltage can be obtained from how many NiMH cells connected in series?

• A. 2
• B. 3
• C. 4
• D. 6

ANS: A

27. A dc voltage is applied across a certain value of resistance. If the resistance value is halved, by what factor must the voltage be multiplied if the dissipated power is unchanged?

• A. 0.5 W
• B. 0.25 W
• C. 4 W
• D. 0.707 W

ANS: D

28. You have an unlimited supply of 1-W, 1000-Ω resistors, and you need a 500-Ω resistance rated at 7 W or more. This can be done by assembling:

• A. Four sets of two 1000-Ω resistors in series, and connecting these four sets in parallel
• B. Four sets of two 1000-Ω resistors in parallel, and connecting these four sets in series
• C. A 3x3 series-parallel matrix of 1000-Ω resistors
• D. Something other than any of the above

ANS: A

29. Where are electrons being pumped in a circuit powered by a battery?

• A. From negative terminal around to positive terminal
• B. from positive terminal around to negative terminal
• C. back and forth from the terminal to terminal
• D. all of the choices

ANS: A

30. Bleeder resistors:

• A. Are connected across the capacitor in a power supply
• B. Keep a transistor from drawing too much current
• C. Prevent an amplifier from being overdriven
• D. Optimize the efficiency of an amplifier

ANS: A

31. Which of the following method/laws defines a node every junction in the network that represents a connection of three or more branches?

• A. Kirchhoff’s Current Law
• B. Kirchhoff’s Voltage Law
• C. Nodal method
• D. Maxwell’s method

ANS: C

32. A major feature of a pot-core winding is:

• A. High current capacity
• B. Large inductance in small volume
• C. Efficiency at very high frequencies
• D. Ease of inductance adjustment

ANS: B

33. As an inductor core material, air:

• A. Has excellent efficiency
• B. Has high permeability
• C. Allows large inductance in a small volume
• D. Has permeability that can vary over a wide range

ANS: A

34. How many nodes are needed to solve an electrical network using nodal method?

• A. All the nodes in the circuit
• B. All nodes less one node
• C. Five nodes
• D. All nodes less two nodes

ANS: B

35. The power loss in an iron-core transformer or other AC devices as a result of magnetic hysteresis

• A. Inductive loss
• B. Hysteresis loss
• C. Magnetic loss
• D. Magnetic power loss

ANS: B

36. What is the inferred absolute zero temperature of silver?

• A. -243°C
• B. -236°C
• C. -234.5°C
• D. -242°C

ANS: A

37. Which of the following materials increase very slightly in resistance with a rise in temperature?

• A. Conductor
• B. Insulator
• C. Dielectric
• D. Alloy

ANS: D

38. What static electricity can be produced by rubbing silk on a glass rod?

• A. Resinous electricity
• B. Vitreous electricity
• C. Positive static electricity
• D. Negative static electricity

ANS: B

39. Determine how long a battery will last whose rating is 100 Ah, 24 V and will run a 300-W electronic equipment and 50-W light.

• A. 26.65 hours
• B. 50.05 hours
• C. 6.85 hours
• D. 12.00 hours

ANS: C

40. The resistance of 575 m of a certain wire of 21.85Ω. How much must be cut off to reduce the resistance to 14.25 Ω?

• A. 375 m
• B. 575 m
• C. 20 m
• D. 200 m

ANS: D

41. If the fifth color in a carbon composition resistor coding is brown, what is the failure rate (%/1000-hr)?

• A. 1
• B. 0.001
• C. 0.1
• D. 0.01

ANS: A

42. Two 0.1 µF capacitors are connected in parallel across a 120-Vdc source. The voltage source is then removed and a third unchanged 0.1 µF capacitor is connected across the parallel combination. What is the voltage across the third capacitor?

• A. 80 V
• B. 60 V
• C. 120 V
• D. 40 V

ANS: A

43. A resistor of 0.0044 siemens, a capacitor whose susceptance is 0.035 Siemens, and a coil whose susceptance is -0.011 siemens are all connected in parallel. The admittance vector is:

• A. 0.0044 + j0.024
• B. 0.035 – j0.011
• C. -0.011 - j0.035
• D. 0.0044 + j0.046

ANS: A

44. Which of the following is negative electricity?

• A. Dynamic electricity
• B. Resinous static electricity
• C. Vitreous static electricity
• D. Vitreous electricity

ANS: B

45. Air works well as a dielectric mainly because it:

• A. Has a high dielectric constant
• B. Is not physically dense
• C. Has low loss
• D. Allows for large capacitance in a small volume

ANS: C

46. Which of the following types of capacitors is polarized?

• A. Paper
• B. Mica
• C. Interelectrode
• D. Electrolytic

ANS: D

47. A copper wire has a resistance of 5 Ω. What is the resistance of another copper wire at the same temperature with length twice as long but with one half the diameter?

• A. 25 Ω
• B. 15 Ω
• C. 40 Ω
• D. 20 Ω

ANS: C

48. To get the Thevenin voltage, you have to

• A. short the voltage source
• B. short the load resistor
• C. open the load resistor
• D. open the voltage source

ANS: C

49. If a capacitor has a negative temperature coefficient:

• A. Its value decreases as the temperature rises
• B. Its value increases as the temperature rises
• C. Its value does not change with temperature
• D. It must be connected with the correct polarity

ANS: A

50. A conductor of unknown length has a diameter of 250 mils and a resistance of 280 Ω. By several successive passes through drawing dies, the diameter is reduced to 50 mils. Assuming that the resistivity of the conductor remains unchanged in the drawing process, what is the resistance of the reduced size wire?

• A. 175 Ω
• B. 250 Ω
• C. 560 Ω
• D. 150 Ω

ANS: A

51. Mercuric oxide is a primary cell with a nominal open circuit voltage of

• A. 1.35 V
• B. 2.1 V
• C. 1.25 V
• D. 1.5 V

ANS: A

52. What resistor is commonly used in power circuits?

• A. Carbon composition resistor
• B. Thin-film resistor
• C. Wire-wound resistor
• D. Potentiometer

ANS: C

53. A coil of 3.50 µH and a capacitor of 47.0 pF are in parallel. The frequency is 9.55 MHz. There is nothing else in series or parallel with these components. What is the admittance vector?

• A. 0 + j0.00282
• B. 0 – j0.00194
• C. 0 + j0.00194
• D. 0 – j0.00758

ANS: B

54. Which of the following is not a characteristic of mica capacitors?

• A. High efficiency
• B. Small size
• C. Capability to handle high voltages
• D. Low loss

ANS: B

55. A vector pointing “southeast” in the GB plane would indicate the following:

• A. Pure conductance, zero susceptance
• B. Conductance and inductive susceptance
• C. Conductance and capacitive susceptance
• D. Pure susceptance, zero conductance

ANS: B

56. Which tolerance color is GMV?

• A. Red
• B. Silver
• C. Gold
• D. Yellow

ANS: D

57. What voltage can be applied across a capacitor for a very short period of time?

• A. Transient voltage
• B. working voltage
• C. Surge voltage
• D. Plate voltage

ANS: C

58. When an alternating voltage reverse in polarity, the current it produces

• A. reverse in direction
• B. has a steady DC value
• C. has a phase angle of 180°
• D. alternate at 1.4 times the frequency of the applied voltage

ANS: A

59. The inductance of a coil can be continuously varied by:

• A. Varying the frequency
• B. Varying the net core permeability
• C. Varying the current in the coil
• D. Varying the wavelength

ANS: B

60. A copper-wire conductor with 0.2 in diameter has an area of

• A. 200 cmil
• B. 20, 000 cmil
• C. 40, 000 cmil
• D. 400 cmil

ANS: C

61. The hot resistance of the tungsten in a bulb is higher than its cold resistance because the filament’s temperature coefficients is

• A. negative
• B. positive
• C. zero
• D. about 10 Ω per degree

ANS: B

62. Which of the following does not increase the loss in a transmission line?

• A. Reducing the power output of the source
• B. Increasing the degree of mismatch between the line and the load
• C. Reducing the diameter of the line conductors
• D. Raising the frequency

ANS: A

63. Power factor is defined as the ratio of:

• A. True power to VA power
• B. True power to imaginary power
• C. Imaginary power to VA power
• D. Imaginary power to true power

ANS: A

64. Which of the following is the temperature coefficient of resistance of silver?

• A. 0.00393
• B. 0.0039
• C. 0.00382
• D. 0.0038

ANS: D

65. In the sign convention of Kirchhoff’s laws, if we traverse in the direction of current in a resistance, it is

• A. voltage rise
• B. voltage drop
• C. positive
• D. negative

ANS: B

66. The shell method of transformer winding:

• A. Provides maximum coupling
• B. Minimizes capacitance between windings
• C. Withstands more voltage than other winding methods
• D. Has windings far apart but along a common axis

ANS: A

67. A type of resistor with typical resistance values range from 2.7 Ω to 22 MΩ

• A. Wire-wound resistor
• B. Carbon composition
• C. Thin-film resistor
• D. Potentiometer

ANS: B

68. What is the dielectric strength of air dielectric?

• A. 150 V/mil
• B. 75 V/mil
• C. 75 V/in
• D. 150 V/in

ANS: B

69. What is current in a chemical cell?

• A. It is a movement of positive hole charges
• B. It is a movement of positive and negative ions
• C. It is a movement of positive ions only
• D. It is a movement of negative ions only

ANS: B

70. To get the Norton current, you have to

• A. short the load resistor
• B. open the voltage source
• C. open the load resistor
• D. short the voltage source

ANS: A

71. Which of the following is the strongest dielectric material?

• A. Glass
• B. Paper
• C. Teflon
• D. Rubber

ANS: A

72. A 2 MΩ resistor and a 2 µF capacitor are connected in series across a 100-V source. How much time is required for the voltage across the capacitor to be 63 V?

• A. 1 s
• B. 2 s
• C. 3 s
• D. 4 s

ANS: D

73. Which of these core types, in general, is best if you need a winding inductance of 1.5 H?

• A. Air core
• B. Ferromagnetic solenoid core
• C. Ferromagnetic toroid core
• D. Ferromagnetic pot core

ANS: D

74. An advantage of a toroid core over a solenoid core is:

• A. The toroid works at higher frequencies
• B. The toroid confines the magnetic flux
• C. The toroid can work for dc as well as for ac
• D. It’s easier to wind the turns on a toroid

ANS: B

75. Which solution to network problems involves a set of independent loop currents assigned to as many as meshes as there are in a circuit?

• A. KCL
• B. KVL
• C. Nodal method
• D. Maxwell’s method

ANS: D

76. In the body-end-dot method of coding for composition/wire-wound/thin-film resistor, the dot represents

• A. First significant digit
• B. Second significant digit
• C. Multiplier
• D. tolerance

ANS: C

77. At five time constants, the transient current is how much percent of its steady state value?

• A. 98.2%
• B. 86.8%
• C. 99.3%
• D. 95%

ANS: C

78. A method of solution applicable only to linear and bilateral networks

• A. Kirchhoff’s laws
• B. Nodal method
• C. Maxwell’s method
• D. Superposition theorem

ANS: D

79. High voltage is used in long-distance power transmission because:

• A. It is easier to regulate than low voltage
• B. The I²R losses are lower
• C. The electromagnetic fields are stronger
• D. Smaller transformers can be used

ANS: B

80. In a household circuit, the 234-V power has:

• A. One phase
• B. Two phases
• C. Three phases
• D. Four phases

ANS: C

81. What is the unit of electric field strength or intensity?

• A. N/C
• B. N/m
• C. V/m
• D. Both A and C

ANS: D

82. The zero-degree phase point in an ac sine wave is usually considered to be the instant at which the amplitude is:

• A. Zero and negative-going
• B. At its negative peak
• C. Zero and positive-going
• D. At its positive peak

ANS: C

83. What is the susceptance (in Siemens) of a circuit if the impedance is 1 – j2 Ω?

• A. 2
• B. 0.1
• C. 0.2
• D. 0.4

ANS: D

84. A coil has a reactance of 4.00 Ω. What is the admittance vector, G + jB, assuming nothing else is in the circuit?

• A. 0 + j0.25
• B. 0 + j4.00
• C. 0 – j0.25
• D. 0 + j4.00

ANS: C

85. If an alternating voltage is given by V = 30 sin 314t, what is the time required by the voltage to reach its negative peak for the first time?

• A. 0.03 s
• B. 0.02 s
• C. 0.015 s
• D. 0.1 s

ANS: C

86. The impedance of an RC circuit is 100 Ω. If the circuit current leads the applied by the voltage by 45˚, then what is the capacitive reactance?

• A. 70.7 Ω
• B. 100 Ω
• C. 141.42 Ω
• D. 50 Ω

ANS: A

87. What will happen to the susceptance of a capacitor if the frequency is doubled, all other things being equal?

• A. It will decrease to half its former value
• B. It will not change
• C. It will double
• D. It will quadruple

ANS: C

88. A 200 V, 50 Hz inductive circuit takes a current of 10 A, lagging 30˚. The inductive reactance of the circuit is

• A. 20 Ω
• B. 10 Ω
• C. 17.32 Ω
• D. 16 Ω

ANS: B

89. What is the power factor of an AC circuit with 6 Ω resistance and 12 Ω inductive reactance?

• A. 0.8 lagging
• B. 0.5 lagging
• C. 0.8 leading
• D. 0.5 leading

ANS: B

90. A capacitor of 1 µF capacitance is charged to 100 V and then disconnected from the power supply. A second but uncharged capacitor of 3 µF is then connected across the first capacitor. The voltage across the parallel combination is

• A. 25 V
• B. 66 2/3 V
• C. 110 V
• D. 45 V

ANS: A

91. Two coils of inductance is 3 H, calculate the equivalent inductance of the combination if mutual inductance assists and if mutual inductance opposes the self-inductance respectively.

• A. 2.4 H and 1.4 H
• B. 6.25 H and 2.75 H
• C. 3.75 H and 0.94 H
• D. 16 H and 4H

ANS: C

92. How is electrical energy wasted in a circuit?

• A. Converted to vibration
• B. Dissipated as light
• C. Dissipated as heat
• D. Converted to radio waves

ANS: C

93. What is the rapidity with which the electrical current changes direction?

• A. period of alternating current
• B. Wavelength of alternating current
• C. frequency of alternating current
• D. ohms

ANS: C

94. What color bands will a resistor of 10 Ω ± 5% tolerance have

• A. Brown, Black, Black, Gold
• B. Brown, Black, Brown, Gold
• C. Brown, Brown, Black, Gold
• D. Brown, Brown, Brown, Gold

ANS: A

95. A current of 0.50 A flows in an electromagnet of negligible resistance when it is connected to a source of 120-V, 60 Hz alternating current. The inductance of the electromagnet is

• A. 0.01 mH
• B. 0.64 H
• C. 0.16 H
• D. 0.24 H

ANS: B

96. In a sine-wave AC circuit with X_L and R in series, the

• A. voltages across R and X_L are in phase
• B. voltages across R and X_L are 180° out of phase
• C. voltage across R lags the voltage across X_L by 90°
• D. voltage across R leads the voltage across X_L by 90°

ANS: C

97. Which of the theorems below is valid only in passive networks?

• A. Maximum power transfer theorem
• B. Compensation theorem
• C. Reciprocity theorem
• D. Millman’s theorem

ANS: C

98. Given a power supply with a no load voltage of 12 volts and full load voltage of 10 volts, what is the percentage of voltage regulation?

• A. 17%
• B. 80%
• C. 20%
• D. 83%

ANS: C

99. After two time constant, the capacitor in an RC circuit is changed to what percentage of the supply voltage?

• A. 36.8%
• B. 63.2%
• C. 36.55%
• D. 95%

ANS: C

100. The power factor of a certain circuit in which the voltage lags behind the current is 80%. To increase the power factor to 100%, it is necessary to add to the circuit additional

• A. resistance
• B. inductance
• C. capacitance
• D. impedance

ANS: B

Complete List of Electronics Engineering Exams: ECE Pre-Board

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This is 100 items set of Practice Examination 11 in Electronics Engineering composed of previous and/or poterntial Board Exams Questions. Read each questions and choices carefully! Choose the best answer. In the actual board, you have to answer 100 items in Electronics Engineering within 5 hours. You have to get at least 70% to pass the subject. Electronics Engineering is 30% of the total 100% Board Rating along with Mathematics (20%), General Engineering and Applied Sciences (20%) and Electronics Systems and Technology (30%).

Start the Test Yourself Exam 11

Choose the letter of the best answer in each questions.

1. A power derating factor of 3.33 mW/°C above 50°C means that

• A. you must decrease the DC power dissipation rating by 3.33 mW for every 1°C rise in the operating temperature above 50°C
• B. you will end up getting a power of 3.33 mW if temperature goes beyond 50°C
• C. you must increase the DC power dissipation rating by 3.33 mW for every 1°C rise in the operating temperature above 50°C
• D. your zener diode will dissipate a nominal DC power of 3.33 mW for temperature above 50°C

ANS: A

2. When you first turn a power supply on, the filter capacitor initially acts as a short circuit thus creating a high initial current that can possibly destroy your rectifier diodes. What is the best way to limit the said current but without sacrificing the output voltage?

• A. use a large-value series current-limiting resistor
• B. use large-value filter capacitors
• C. use inductive filters instead of capacitive filters
• D. don’t turn off your power supply

ANS: C

3. The electromagnetic force induced between a varying magnetic field and a stationary conductor.

• A. Mutually induced EMF
• B. Self-induced EMF
• C. Electro statically induced EMF
• D. Statically induced EMF

ANS: D

4. A wire has a resistance of 5 Ω at room temperature and a temperature coefficient α = 4 × 10^-3/°C. Calculate the wire resistance if the temperature rises by 75°C.

• A. 6.5 Ω
• B. 6.1 Ω
• C. 6 Ω
• D. 6.16 Ω

ANS: A

5. A combination of two charges with equal charge magnitude but opposite signs.

• A. magnetic dipole
• B. static dipole
• C. dynamic dipole
• D. electric dipole

ANS: D

6. If a dc electromagnetic of 10-V produces a steady-state current of 100-mA in a 100 Ω coil, how much will the current be after 0.2 sec?

• A. 63 mA
• B. 100 mA
• C. 37 mA
• D. 200 Ma

ANS: A

7. What is the time constant of a 20-H coil having 100 Ω of series resistance?

• A. 5 s
• B. 0.5 s
• C. 0.2 s
• D. 20 ms

ANS: C

8. If the RC time constant is given to be 1 s, how long will it take for the voltage to drop from 100 V to 50 V?

• A. 0.63 s
• B. 0.37 s
• C. 0.5 s
• D. 0.7 s

ANS: D

9. The effect of little change in magnetic flux density when magnetic field intensity increases.

• A. Retentivity
• B. Coercivity
• C. Saturation
• D. Permeability

ANS: C

10. A series resonant circuit at 0.2 MHz develops 100 mV across a 250 µH coil with a 2 mV input. Calculate Q.

• A. 50
• B. 25
• C. 100
• D. 200

ANS: A

11. A point in magnet where the intensity of magnetic lines of force is a maximum.

• A. North Pole
• B. Saturation Point
• C. Coercive point
• D. Magnetic pole

ANS: D

12. An oscillator circuit that has two capacitors and one inductor on its feedback network

• A. Colpitts
• B. Clapp
• C. Hartley
• D. Pierce Crystal

ANS: A

13. The ability of a substance of getting magnetized is called

• A. Retentivity
• B. Permeability
• C. Coercivity
• D. Susceptibility

ANS: D

14. A 12 volt battery is connected to a 5 cm, 350 turn coil with resistance of 15-Ω. What is the field strength produced in Oe?

• A. 70
• B. 280
• C. 56
• D. 353

ANS: A

15. A magnetic material has a relative permeability of 500. What is the absolute permeability of the material in cgs system?

• A. 500
• B. 630 H/m
• C. 500 G/Oe
• D. 630 x 10^-6 G/Oe

ANS: C

16. The reciprocal of reluctance corresponds to what in electric circuits?

• A. Permeance
• B. Admittance
• C. Impedance
• D. Conductance

ANS: D

17. A material with negative temperature coefficient means

• A. Its resistance will increase as temperature increases
• B. Its resistance will decrease as temperature decreases
• C. Its resistance will increase as temperature decreases
• D. Its resistance will decrease as temperature increases

ANS: D

18. A 12-V battery with a capacity of 100 A-hr is used to supply 300-W electronic equipment and a 25 W light. How long will this battery last?

• A. 7.38 hours
• B. 3.69 hours
• C. 5.22 hours
• D. 2.61 hours

ANS: A

19. The physical motion that is due to the forces of magnetic fields

• A. Repulsion
• B. Attraction
• C. Motor Action
• D. Rotation

ANS: C

20. Which of these statements is FALSE about the relationship of the magnetic force on a moving charge?

• A. A magnetic force does not point in the direction of the field or in the direction of the charge’s velocity
• B. A magnetic force is exerted on a moving electric charge
• C. No magnetic force is exerted on a charge at rest
• D. A magnetic force is exerted on a charge moving along the direction of the magnetic field

ANS: B

21. Indicate which of the following statements is FALSE.

• A. Capacitive reactance is a measure of the reaction of C to a change in voltage
• B. RC time constant is a measure of the reaction of C to a change in voltage
• C. The concept of reactance is useful for both sine wave AC circuits and non-sinusoidal waveforms
• D. The method of time constant is used to analyze both sinusoidal and non-sinusoidal waveforms

ANS: C

22. It is the ability of an insulator to concentrate electric flux

• A. Permeability
• B. Susceptibility
• C. Permittivity
• D. Retentivity

ANS: C

23. It is commonly used for precision wire-wound resistors, which do not change resistance when the temperature increases

• A. carbon
• B. aluminum
• C. constantan
• D. iron

ANS: C

24. Which of the following statements is true about the force on a current-carrying straight conductor in a magnetic field?

• A. With the conductor at 90°, the reaction between two magnetic fields is minimum
• B. With the conductor at 0°, there is no effect between them
• C. With the conductor is at angle between 0° and 90°, only the parallel component is effective
• D. A motor action can be produced if the conductor is placed parallel to the magnetic field

ANS: B

25. It is known as the breakdown voltage of a dielectric material.

• A. relative permittivity
• B. dielectric strength
• C. velocity reduction ratio
• D. velocity factor

ANS: B

26. Find the value and tolerance of a resistor having bands of the following: Red, Violet, Green, Silver.

• A. 27 MΩ ±10%
• B. 2.7 MΩ ±10%
• C. 27 kΩ ±10%
• D. 2.7 kΩ ±10%

ANS: B

27. Thevenin’s theorem replaces a complicated circuit facing a load by an

• A. ideal voltage source and parallel resistor
• B. ideal voltage source and series resistor
• C. ideal current source and parallel resistor
• D. ideal current source and series resistor

ANS: B

28. In a sine wave AC circuit with inductive reactance, the

• A. phase angle of the circuit is always 45°
• B. voltage across the inductance must be 90° out of phase with the applied voltage
• C. current through the inductance lags its induced voltage by 90°
• D. current through the inductance and voltage across it are 180° out of phase

ANS: C

29. What negative feedback type increases both the input and output impedances of an amplifier?

• A. Voltage-shunt
• B. Current-shunt
• C. Voltage-series
• D. Current-series

ANS: D

30. A linear circuit is one whose parameters (e.g. resistances, etc)

• A. change with change in current
• B. change with change in voltage
• C. do not change with voltage and current
• D. are bilateral

ANS: C

31. Ten volts is applied across R₁, R₂, and R₃ is series, producing 1 A in the series circuit. R₁ equals 6 Ω and R₂ equals 2 Ω. Therefore, R₃ equals

• A. 2 Ω
• B. 10 Ω
• C. 4 Ω
• D. 12 Ω

ANS: A

32. A 0.5-C charge is moving at ratio of 5 cm/s. What is the current at 2 sec?

• A. 0.25 A
• B. 10 A
• C. 0.025 A
• D. 0.10 A

ANS: A

33. The fifth strip of a precision film resistor color code represents

• A. tolerance
• B. temperature
• C. failure rate
• D. multiplier

ANS: A

34. Find the value of a capacitor in picofarads having the following color bands: Yellow, Violet, Brown, Black, Yellow

• A. 47 pF ±10%
• B. 470 pF ±10%
• C. 47 pF ±20%
• D. 470 pF ±20%

ANS: D

35. A meter-sensitivity control in a test instrument would probably be:

• A. A set of switchable, fixed resistors
• B. A linear-taper potentiometer
• C. A logarithmic-taper potentiometer
• D. A wirewound resistor

ANS: B

36. At what temperature a magnetic material will lose its ferromagnetic properties?

• A. Curie temperature
• B. Absolute temperature
• C. ambient temperature
• D. room temperature

ANS: A

37. What is Coulomb’s first law of electrostatics?

• A. Like poles repel unlike poles attract each other
• B. Like charges repel unlike charges attract each other
• C. Unlike poles repel and like poles attract each other
• D. Unlike charges repel and like charges attract each other

ANS: B

38. A volume control in a stereo compact-disc player would probably be:

• A. A set of switchable, fixed resistors
• B. A linear-taper potentiometer
• C. A logarithmic-taper potentiometer
• D. A wirewound resistor

ANS: C

39. A conductor in which two oscillating circuit have the same resonant frequency is called

• A. Gimmick
• B. Synthony
• C. Puff
• D. Wet contact

ANS: B

40. The effect UV radiation that discharges a negatively charged body in a vacuum is called

• A. Joule effect
• B. Hallwachs effect
• C. Hall Effect
• D. Joshi effect

ANS: A

41. If a wire conductor of 0.1 resistance is doubled in length, its resistance becomes

• A. 0.01 Ω
• B. 0.02 Ω
• C. 0.2 Ω
• D. 0.05 Ω

ANS: C

42. On what basis is the size of the filter capacitor selected?

• A. short RC time constant
• B. power rating
• C. voltage rating
• D. long RC time constant

ANS: C

43. Those magnetic materials are best suited for making armature and transformer cores which have _____ permeability and ______ hysteresis loss.

• A. high, high
• B. high, low
• C. low, low
• D. low, high

ANS: B

44. A capacitor charged to 100 V and is then switched across a resistor. When the voltage across the capacitor has fallen to 14 V, the duration of the discharge as measured in time constants, is approximately

• A. 0.3
• B. 2.0
• C. 1.0
• D. 2.5

ANS: B

45. Preventing one material from affecting one another through their common electric or magnetic hysteresis

• A. grounding
• B. Hall Effect
• C. shielding
• D. limiting

ANS: C

46. If the tolerance color is violet, this means a tolerance of

• A. 0.1%
• B. 0.5%
• C. 0.25%
• D. 1%

ANS: A

47. A fully charged lead-acid battery will indicate a specific gravity reading between

• A. 1.175 to 1.200
• B. 1.225 to 1.250
• C. 1.200 to 1.225
• D. 1.275 to 1.300

ANS: D

48. Find the phase angle between the voltages across the current through the circuit when X_C is 25 ohms, R is 100 ohms and X_L is 100 ohms are in series.

• A. 53.1 degrees with the voltage lagging the current
• B. 36.9 degrees with the voltage leading the current
• C. 53.1 degrees with the voltage leading the current
• D. 36.9 degrees with the voltage lagging the current

ANS: D

49. For Kirchhoff’s voltage law, circuits are divided into which of the following?

• A. Series-parallel circuits
• B. Nodes
• C. Ohms
• D. Loops

ANS: D

50. The ability of a conductor to pass or the opposite of resistance?

• A. Reactance
• B. Capacitance
• C. Resistance
• D. Conductance

ANS: D

51. The resistance of a coil wire increases from 40 Ω at 10°C to 48.25 Ω at 60°C. Find the temperature coefficient at 0°C of the conductor material.

• A. 0.0043
• B. 0.00493
• C. 0.00393
• D. 0.0053

ANS: A

52. A length of wire has a resistance of 6 Ω. What is the resistance of wire of the same material three times as long as twice the cross-sectional area?

• A. 36 Ω
• B. 12 Ω
• C. 9 Ω
• D. 01 Ω

ANS: C

53. Which of the following statements is TRUE?

• A. An Ideal current source cannot be in parallel with a short circuit
• B. An ideal voltage source can be in parallel with an open circuit
• C. An ideal current source can be in series with an open circuit
• D. An ideal voltage source cannot be in series with an ideal current source

ANS: B

54. Halving the cross-sectional area of a conductor will

• A. Not affect the resistance
• B. Half the resistance
• C. Quarter the resistance
• D. Double the resistance

ANS: D

55. Given a power supply with a full load voltage of 200 volts and a regulation of 25%, what is the no load voltage?

• A. 150 volts
• B. 240 volts
• C. 160 volts
• D. 250 volts

ANS: D

56. A coil has 6,000 turns of wire and a resistance of 380 Ω. The coil is rewound with the same quantity (weight) of wire, but has 13,400 turns. How many Ω will the new coil have?

• A. 1895 Ω
• B. 1905 Ω
• C. 1825 Ω
• D. 1792 Ω

ANS: A

57. What is the average power dissipated by an electric heater with resistance of 50 Ω drawing a current of 20 sin 30t A?

• A. 0 kW
• B. 10 kW
• C. 14.14 kW
• D. 20 Kw

ANS: B

58. Those materials are well suited for making permanent magnets which have ______ retentivity and _____ coercivity.

• A. low, low
• B. high, high
• C. low, high
• D. high, low

ANS: B

59. A backwards-working electric motor is best described as:

• A. An inefficient, energy-wasting device
• B. A motor with the voltage connected the wrong way
• C. An electric generator
• D. A magnetic-field generator

ANS: C

60. What measurements are required to determine the phase angle of a single-phase circuit?

• A. The power in watts consumed by the circuit
• B. The frequency, capacitance and inductance
• C. The power in watts, voltage and current
• D. The resistance, current and voltage

ANS: C

61. An AC circuit consisting of a capacitor, an inductor and a resistor in series is a resonant when the

• A. in-phase current equals the out-of-phase current
• B. maximum current passes through the circuit
• C. power dissipation is minimum
• D. power factor is zero

ANS: B

62. What is the value of the peak factor for a pure sine wave?

• A. 1.414
• B. 0.637
• C. 0.707
• D. 1.11

ANS: A

63. The conductance and inductive susceptance of a circuit have the same magnitude. What is the power factor of the circuit?

• A. 1
• B. 0.707
• C. 0.5
• D. 0.866

ANS: B

64. A circuit has a resonant frequency of 455 KHz and a bandwidth of 57.2 KHz. Find the Q of the circuit.

• A. 795
• B. 79.5
• C. 0.795
• D. 7.95

ANS: D

65. In a parallel-resonant circuit, what is the relationship between impedance and current?

• A. Minimum impedance, minimum current
• B. Minimum impedance, maximum current
• C. Maximum impedance, minimum current
• D. Maximum impedance, maximum current

ANS: C

66. A 15 µC point charge is located on the y-axis at (0, 0.25). A second charge of 10 µC is located on the x-axis at (0.25, 0). If the two charges are separated by air, what is the force between them?

• A. 0.0982 N
• B. 33.93 N
• C. 0.341 N
• D. 10.79 N

ANS: D

67. A cell connection, providing a higher voltage than a single cell with no increase in current.

• A. Ground connected
• B. Parallel connected
• C. Series connected
• D. Series-parallel connected

ANS: C

68. A power transforming device, one that converts energy into some other form

• A. Converter
• B. Transducer
• C. Transformer
• D. Transmuter

ANS: D

69. Refers to charging and discharging of secondary cells?

• A. Re-charging of cell
• B. Re-aligning of cell
• C. Polarizing of cell
• D. Cycling of cell

ANS: D

70. What static electricity can be produced by rubbing fur on a rubber, amber, or plastic rod?

• A. Resinous static electricity
• B. Positive static electricity
• C. Vitreous static electricity
• D. Negative static electricity

ANS: A

71. What do you call the space between and around charged bodies?

• A. Magnetic field
• B. Electromotive force
• C. Electromagnetic field
• D. Electrostatic field

ANS: D

72. In RC circuits, the time constant indicates the time it takes a capacitor to charge up to what percent of the charging voltage?

• A. 100%
• B. 63%
• C. 67%
• D. 31%

ANS: B

73. A 0.01 m by 0.02m solar cell has a conversion efficiency of 9%. The maximum power rating of the device is

• A. 18 mW
• B. 180 mW
• C. 1800 kW
• D. 180 Kw

ANS: A

74. A practical type of capacitor used to demonstrate static electricity.

• A. Mycalex
• . Muller tube
• C. Geiger counter
• D. Leyden jar

ANS: D

75. What does a gold third band represent?

• A. 0.01 multiplier
• B. 5% tolerance
• C. a 10% tolerance
• D. a 0.1 multiplier

ANS: D

76. What does a fifth band on a resistor indicate?

• A. reliability
• B. sensitivity
• C. life
• D. no fifth band

ANS: B

77. DC motors and stepper motors are mainly used in robots instead of AC motors because they can

• A. be electronically controlled
• B. be operated by electric pulses
• C. withstand large overloads
• D. run at varying speed

ANS: B

78. The production of hydrogen gas caused by a portion of a charge current breaking down the water in the electrolytes

• A. Electrolysis
• B. Hydrogenation
• C. Hydrolysis
• D. Gassing

ANS: D

79. Length of twisted two-conductor cable used as a variable capacitive load in which, untwisting and separating the individual conductors vary the capacitance.

• A. Gimmick
• B. Syntony
• C. Puff
• D. Wet contact

ANS: A

80. The length of cylindrical capacitor is 10mm. The outer diameter of its single core cable conductor is 3 mm surrounded by a paper insulation of outer diameter 6 mm. What is its capacitance?

• A. 2.0 µF
• B. 2.5 µF
• C. 2.0 pF
• D. 2.5 Pf

ANS: C

81. What electrical quantity is measured by a watt-hour meter?

• A. Current
• B. Energy
• C. Voltage
• D. Power

ANS: B

82. The phenomenon whereby current in a gas changes as a result of irradiation by light is called

• A. Joule effect
• B. Hall Effect
• C. Joshi effect
• D. Hallwachs Effect

ANS: C

83. Three capacitors A, B and C are charged as follows: A = 10 µF at 100 V, B = 15 µF at 150 V and C = 25 µF at 200 V. They are then connected in parallel with terminals of like polarity together. What is the voltage across the combination?

• A. 156 V
• B. 256 V
• C. 165 V
• D. 265 V

ANS: C

84. A disadvantage of mercury cells and batteries is that:

• A. They don’t last as long as other types.
• B. They have a flat discharge curve.
• C. They pollute the environment.
• D. They need to be recharged often.

ANS: C

85. How long does it take for an initial charge of 20 V_DC to decrease to 0.37 V_DC in a 0.01 µF capacitor when a 2 MΩ resistor is connected across it?

• A. 0.08 second
• B. 0.4 second
• C. 0.6 second
• D. 0.2 second

ANS: A

86. If a resistance to which a constant voltage is applied is halved, what power dissipation will result?

• A. Doubled
• B. Quadrupled
• C. Halved
• D. Stay the same

ANS: A

87. A substance with high retentivity is best suited for making:

• A. An ac electromagnet
• B. A dc electromagnet
• C. An electrostatic shield
• D. A permanent magnet

ANS: D

88. A significant advantage, in some situations, of a toroidal coil over a solenoid is:

• A. The toroid is easier to wind
• B. The solenoid cannot carry as much current
• C. The toroid is easier to tune
• D. The magnetic flux in a toroid is practically all within the core

ANS: D

89. The process of converting chemical energy into electrical energy in a cell.

• A. Electron flow
• B. Electrolysis
• C. Polarization
• D. Electrochemical action

ANS: D

90. The portion of apparent power dissipated in a circuit

• A. Phase power
• B. True power
• C. Power factor
• D. Apparent power factor

ANS: B

91. Waves in alternating current can involve

• A. regular changes in voltages levels
• B. regular changes in current levels
• C. regular changes in the direction of the electron flow
• D. all of the above

ANS: D

92. In a triangular or sawtooth waveform, the RMS is how many times the peak value?

• A. 0.577
• B. 0.500
• C. 0.707
• D. 0.15

ANS: A

93. For an inductor or coil, which of the following indicates how low the losses are?

• A. Quality factor
• B. Inductive reactance
• C. Power factor
• D. Impedance

ANS: A

94. A certain wire has a resistance R. The resistance of another wire identical with the first except for having twice its diameter is

• A. 4R
• B. 2R
• C. R/2
• D. R/4

ANS: D

95. Copper is the second best conductor of electricity with ______ free electrons per in³.

• A. 1.68 x 10²⁴
• B. 1.64 x 10²⁴
• C. 1.6 x 10²⁴
• D. 1.66 x 10²⁴

ANS: B

96. A resistor with the color-coded value of 100 Ω and ±20 percent tolerance can have an actual resistance between

• A. 80 and 120 Ω
• B. 98 and 102 Ω
• C. 90 and 110 Ω
• D. 100 and 120 Ω

ANS: A

97. What is the basic purpose of all electrical and electronic system that are designed and built?

• A. to manipulate information
• B. to do work
• C. to do work and manipulate information
• D. to generate information

ANS: C

98. What is the typical leakage resistance of a paper capacitor?

• A. 109 Ω
• B. 105 Ω
• C. 1011 Ω
• D. 1010 Ω

ANS: A

99. Tantalum electrolytic capacitor has a typical value that ranges from

• A. 1 µF to 22000 µF
• B. 5 pF to 1 µF
• C. 1 µF to 1000 µF
• D. 1 nF to 100 µF

ANS: C

100. A transformer has 500 turns in the primary and 1500 in the secondary. Assuming no losses, if 45 V is applied to the primary what is the voltage developed in the secondary?

• A. 180 V
• B. 13.5 V
• C. 135 V
• D. 90 V

ANS: C

Complete List of Electronics Engineering Exams: ECE Pre-Board

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This is 100 items set of Practice Examination 10 in Electronics Engineering composed of previous Board Exams Questions. Read each questions and choices carefully! Choose the best answer. In the actual board, you have to answer 100 items in Electronics Engineering within 5 hours. You have to get at least 70% to pass the subject. Electronics Engineering is 30% of the total 100% Board Rating along with Mathematics (20%), General Engineering and Applied Sciences (20%) and Electronics Systems and Technology (30%).

Start the Test Yourself Exam 10

Choose the letter of the best answer in each questions.

1. What probable effect on the human body if subjected to a current of 40 to 100 mA, 60 Hz, AC or 160 to 300 mA, DC?

• A. Respiratory failure
• B. Perception
• C. Reflex action
• D. Mascular inhibition

2. What probable effect on the human body if subjected to a current of over 100 mA, 60 Hz, AC or 300 mA, DC?

• A. Respiratory failure
• B. Fatal
• C. Reflex action
• D. Mascular inhibition

3. What refers to the jarring, shaking sensation you receive from contact with electricity?

• A. Respiratory failure
• B. Electric shock
• C. Fatal
• D. Mascular inhibition

4. Mechanical rotation frequency is measured using a device called ______.

• A. frequency counter
• B. frequency meter
• C. accelerometer
• D. tachometer

5. Electrical-output frequencies of ac generators can be measured by ______.

• A. vibrating-reed devices or tuned circuits
• B. accelerometer
• C. frequency meter
• D. tachometer

6. Audio frequencies can be measured by a process known as ______.

• A. frequency counting
• B. zero beating
• C. beating
• D. mixing

7. What is another term for zero beating?

• A. Frequency counting
• B. Heterodyning
• C. Beating
• D. Mixing

8. What wavemeter is used for measuring frequencies in the microwave range?

• A. Frequency counter
• B. Bolometer
• C. Cavity wavemeter.
• D. Absorption wavemeter

9. What is the process of matching an unknown signal with a locally generated signal of the same frequency obtained from a calibrated high-precision oscillator?

• A. Frequency counting
• B. Zero beating
• C. Beating
• D. Mixing

10. What device that sweeps over a band of frequencies to determine what frequencies are being produced by a specific circuit under test and the amplitude of each frequency component?

• A. Frequency counter
• B. Bolometer
• C. Cavity wavemeter
• D. Spectrum analyzer

11. What is commonly used for the analysis of waveforms generated by electronic equipment?

• A. Frequency counter
• B. Cavity wavemeter
• C. Cathode-Ray Oscilloscope (CRO or O-SCOPE)
• D. Bolometer

12. What is device used to measure frequencies above the audio range?

• A. Frequency counter
• B. Cavity wavemeter
• C. Bolometer
• D. Electronic Frequency Counter

13. What are calibrated resonant circuits used to measure frequency?

• A. Frequency counter
• B. Wavemeters
• C. Cavity wavemeter
• D. Spectrum analyzer

14. What is the difference in frequency between the oscillator frequency and the unknown frequency?

• A. Beat frequency
• B. lF
• C. Image frequency
• D. Signal frequency

15. The rotation frequency of recording devices and teletypewriter motors can be measured by the use of a ______.

• A. Tachometer
• B. Oscilloscope
• C. Frequency counter
• D. Stroboscope

16. What is an instrument that allows you to view rotating or reciprocating objects intermittently and produces the optical effect of a slowing down or stopping motion?

• A. Tachometer
• B. Oscilloscope
• C. Frequency counter
• D. Stroboscope

17. What is an electronic flash device in which the flash duration is very short, a few millionths of a second and can measure very rapid motion?

• A. Tachometer
• B. Strobotac
• C. Frequency counter
• D. Stroboscope

18. What is a combination of watch and revolution counter?

• A. Chronometric tachometer
• B. Frequency counter
• C. Strobotac
• D. Stroboscope

19. What type of bolometer is characterized by an increase in resistance as the dissipated power rises?

• A. Chronometric tachometer
• B. Strobotac
• C. Barretter
• D. Stroboscope

20. What type of bolometer is characterized by decrease in resistance as the power increases?

• A. Chronometrictachometer
• B. Strobotac
• C. Barretter
• D. Thermistor

21. What instrument is used for measuring radio frequency (rf) power?

• A. Thermocouple ammeter
• B. Strobotac
• C. Barretter
• D. Thermistor

22. When using strobotac, at what speed is "flicker" becomes a problem because the human eye can retain successive images long enough to create the illusion of continuous motion?

• A. 600 rpm
• B. 500 rpm
• C. 1200 rpm
• D. 300 rpm

23. What is the approximate life of the strobotron lamp if used at flashing speeds of less than 5,000 rpm?

• A. 250 hours
• B. 500 hours
• C. 1200 hours
• D. 300 hours

24. What is the approximate life of the strobotron lamp if used at flashing speeds of more than 5,000 rpm?

• A. 250 hours
• B. 500 hours
• C. 100 hours
• D. 300 hours

25. What are used as filters for the passage or rejection of specific frequencies?

• A. Tuned circuits
• B. Filter circuits
• C. Band pass filter
• D. High pass filter

26. An elementary, single coil, dc generator will have an output voltage with how many pulsations per revolution?

• A. One
• B. Two
• C. Three
• D. Four

27. How many commutator segments are required in a two-coil generator?

• A. One
• B. Two
• C. Three
• D. Four

28. How can field strength be varied in a practical dc generator?

• A. By varying the input voltage to the field coils
• B. By varying the output voltage to the field coils
• C. By increasing the number of field windings
• D. By decreasing the number of field windings

29. Are dc generators that are designed to act as high-gain amplifier?

• A. Amplidynes
• C. Dynamos
• B. Synchros
• D. Servos

30. The power output of the amplidynes may be up to _______ times larger than the power input to its control windings.

• A. 100,000
• B. 10,000
• C. 1,000
• D. 100

31 .What generators have both series field windings and shunt field windings?

• A. Universal generator
• B. Series-wound dc generator
• C. Parallel-wound dc generator
• D. Compound-wound dc generators

32. The substrate of an N-channel MOSFET is made of what material?

• A. P-type material
• B. N-type material
• C. Intrinsic material
• D. Extrinsic material

33. In a MOSFET, which element is insulated from the channel material?

• A. The source terminal
• B. The gate terminal.
• C. The substrate terminal.
• D. The drain terminal.

34. What type of MOSFET can be independently controlled by two separate signals?

• A. The single-gate MOSFET.
• B. The four-gate MOSFET.
• C. The dual-gate MOSFET.
• D. The dual-drain MOSFET.

35. What is the purpose of the spring or wire around the leads of a new MOSFET?

• A. To prevent damage from static electricity.
• B. To prevent damage from dynamic electricity.
• C. To prevent damage from intense pressure. W
• D. To prevent damage from intense temperature.

36. What is a typical light-to-dark resistance ratio for a photocell?

• A. 1:1000
• B. 1:10000
• C. 1:2000
• D. 1:20000

37. What semiconductor device produces electrical energy when exposed to light?

• A. Photoelectronic cell
• B. Photovoltaic cell
• C. Photoelectric cell
• D. Optoelectronic device

38. The UJT has how many PN junctions?

• A. One
• B. Two
• C. Three
• D. Four

39. The area between base 1 and base 2 in a UJT acts as what type of common circuit component?

• A. Variable inductor
• B. Variable capacitor
• C. Variable resistor
• D. Fixed resistor

40. The sequential rise in voltage between the two bases of the UJT is called what?

• A. A voltage spike
• B. A voltage gradient
• C. A voltage peak
• D. A voltage surge

41 .What is the normal current path for a UJT?

• A. From base 1 to the emitter.
• B. From base 1 to base 2.
• C. From base 2 to the emitter.
• D. From input to output.

42. What is one of the primary advantages of the FET when compared to the bipolar transistor?

• A. Low input impedance.
• B. High input impedance.
• C. Low output impedance.
• D. High output impedance.

43. The SCR is primarily used for what function?

• A. The SCR is primarily used for amplifying.
• B. The SCR is for both switching and amplifying.
• C. The SCR is primarily used for switching power on or off.
• D. The SCR is for any electronic application.

44. When an SCR is forward biased, what is needed to cause it to conduct?

• A. A drain signal.
• B. A source signal.
• C. A anode signal.
• D. A gate signal.

45. What is the only way to cause an SCR to stop conducting?

• A. The forward bias must be reduced below the minimum conduction level.
• B. The forward bias must be increased above the minimum conduction level.
• C. The forward bias must be equal to the minimum conduction level.
• D. The reverse bias must be reduced below the minimum conduction level.

46. The TRIAC is similar in operation to what device?

• A. SCS
• B. UJT
• C. SCR
• D. DIAC

47. When used for ac current control, during which alternation of the ac cycle does the TRIAC control current flow?

• A. During both alternations.
• B. With only one alternation.
• C. During positive alternation only.
• D. During negative alternation only.

48. What type of bias is required to cause an LED to produce light?

• A. Forward bias
• B. Reverse bias
• C. Either A or B
• D. Neither A or B

49. When compared to incandescent lamps, what is the power requirement of an LED?

• A. Very high
• B. High
• C. Very low
• D. Low

5O. The varactor displays what useful electrical property?

• A. Variable resistance
• B. Variable capacitance
• C. Variable inductance
• D. Variable frequency

51. When a PN junction is forward biased, what happens to the depletion region?

• A. The depletion region decreases.
• B. The depletion region increases.
• C. The depletion region disappears.
• D. The depletion region remains the same.

52. When the reverse bias on a varactor is increased, what happens to the effective capacitance?

• A. Capacitance increases.
• B. Capacitance decreases.
• C. Capacitance remains the same.
• D. Temperature coefficient increases.

53. In a reverse biased PN-junction, which current carriers cause leakage current?

• A. The majority carriers.
• B. The minority carriers.
• C. The majority and minority carriers.
• D. Either the majority or minority carriers.

54. The action of a PN-junction during breakdown can be explained by what two theories?

• A. Zener effect and avalanche effect.
• B. Zener and flywheel effects.
• C. Avalanche and flywheel effects
• D. Zener and Miller effects.

55. Which breakdown theory explains the action that takes place in a heavily doped PN-junction with a reverse bias of less than 5 volts?

• A. Miller effect
• B. Avalanche effect
• C. Zener effect
• D. Flywheel effect

56. The plate voltage of a tube will vary 126 volts when a 3-volt ac signal is applied to the control grid. What is the gain of this tube?

• A. 32
• B. 42
• C. 52
• D. 62

57. lf the mu of a tube is 85 and the signal at the control grid is 4 volts ac, the plate voltage will vary by what amount?

• A. 340 V
• B. 120 V
• C. 240 V
• D. 220 V

58. The suppressor grid is added to a tetrode to reduce what undesirable characteristic of tetrode operation?

• A. Primary emission
• B. Secondary emission
• C. Tertiary emission
• D. Quaternary emission

59. What type of bias requires constant current flow through the cathode circuit of a triode?

• A. Anode biasing
• B. Fixed biasing
• C. Cathode biasing
• D. Self biasing

6O. How are computers classified?

• A. Technology
• B. Data they handle
• C. Purpose
• D. All of the choices

61. Mechanical computers are considered to be of what type?

• A. Analog
• B. Digital
• C. Special
• D. General

62. In a general-purpose computer, the ability to perform a wide variety of operations is achieved at the expense of what capabilities?

• A. Speed and accuracy
• B. Speed and memory capacity
• C. Speed and efficiency
• D. Speed and versatility

63. All analog computers are what type of computers?

• A. Special-purpose
• B. Electromechanical
• C. Mechanical
• D. First generation

64. What are analog computers designed to measure?

• A. Electrical quantities
• B. Physical quantities
• C. Natural quantities
• D. Continuous electrical or physical conditions.

65. Early analog computers were what type of devices?

• A. Mechanical or electromechanical
• B. Solid state type
• C. Vacuum type
• D. Electrical

66. What are computers called that combine the functions of both analog and digital computers?

• A. Versatile computers
• B. Hybrid computers
• C. Anadigi computers
• D. Mainframe computers

67. What is the temperature range within which a disk will operate?

• A. 10 to 50 degrees Celsius
• B. 10 to 15 degrees Celsius
• C. 20 to 60 degrees Celsius
• D. 50 to 100 degrees Celsius

68. What is the most basic type of filter?

• A. The capacitor filter
• B. Inductor filter
• C. LC filter
• D. Mechanical filter

69. What is the range of values usually chosen for a choke?

• A. From 20 to 100 H
• B. From 1 to 20 H
• C. From 1 to 10 H
• D. From 10 to 20 H

7O. What is the ripple frequency of a full-wave rectifier with an input frequency of 60 Hz?

• A. 120 Hz
• B. 240 Hz
• C. 60 Hz
• D. 360 Hz

71. A standard programming language of the U.S. defense department similar to Pascal.

• A. Ada
• B. BASlC
• C. C + +
• D. RPG

72. The electron tube replaces what component in an electron tube voltage regulator?

• A. Variable inductor
• B. Variable capacitor
• C. Variable resistor
• D. Transistor

73. Which of the following is referred to as organized data?

• A. Source
• B. Information
• C. Input
• D. Output

74. What is the common mode rejection ratio of an ideal differential amplifier?

• A. Infinity
• B. Unity
• C. Less than unity
• D. Zero

75. The type of feedback used to improve the fidelity of an amplifier and to increase its frequency response.

• A. Fidelity feedback
• B. Positive feedback
• B. Unwanted feedback
• D. Negative feedback

76. A negatively charge atom is sometimes called ______.

• A. electron
• B. cation
• C. anion
• D. ion

77. If the magnitude of the potential difference is generated by a single conductor passing through a magnetic field, which of the following statements is false?

• A. The potential difference depends on the speed with which the conductor cuts the magnetic field.
• B. The potential difference depends on the length of the conductor that cuts the magnetic field.
• C. The potential difference depends on the magnetic field density that is present.
• D. The potential difference depends on the diameter of the conductor that cuts the magnetic field.

78. What is the internal resistance of a 9 V battery that delivers 100 A when its terminals are shorted?

• A. 0.09 Ω
• B. 11 Ω
• C. 1.0 Ω
• D. 90 Ω

79. Which of the following statements is true?

• A. An ideal current source cannot be in parallel with a short circuit.
• B. An ideal voltage source can be in parallel with an open circuit.
• C. An ideal current source can be in series with an open circuit.
• D. An ideal voltage source cannot be in series with an ideal current source.

80. What is the average power dissipated by an electric heater with resistance of 50 Ω drawing a current of 20sin (30t) A?

• A. 0 kW
• B. 10 kW
• C. 14.14 kW
• D. 20 kW

81. What measurements are required to determine the phase angle of a single-phase circuit?

• A. The power in watts consumed by the circuit.
• B. The frequency, capacitance and inductance.
• C. The power in watts, voltage and current
• D. The resistance, current and voltage.

82. The conductance and inductive susceptance of a circuit have the same magnitude. What is the power factor of the circuit?

• A. 1
• B. 0.707
• C. 0.5
• D. 0.866

83. A circuit has a resonant frequency of 455 kHz and a bandwidth of 57.2 kHz. Find the Q of the circuit.

• A. 795
• B. 79.5
• C. 0.795
• D. 7.95

84. A semiconductor logic output which pulls neither to a high nor a low voltage state.

• A. Logic 1
• B. Floating state
• C. Logic 0
• D. Limbo

85 An intrinsic semiconductor has some holes in it at room temperature. What causes these holes?

• A. Doping process
• B. ionization
• C. Thermal energy
• D. Radiant flux

86. Refers to a field surrounding electrons and protons at stationary period indicating a stored energy.

• A. Magnetic field
• B. Electron field
• C. Electrostatic field
• D. Electrodynamic Held

87. The time required to complete one cycle of a waveform.

• A. Wavetime
• B. Wavelength
• C. Frequency
• D. Period

88. Lines of flux that do not follow the intended path.

• A. Flux loss
• B. Leakage flux
• C. lnductance leakage
• D. Hysteresis loss

89. What consists of elements inseparably associated and formed on a single substrate?

• A. Micro-circuit
• B. Integrated circuit
• C. Module
• D. PCB

90. What determines whether a substance is an insulator or a conductor?

• A. Number of protons
• B. Number of photons
• C. Number of valence electrons
• D. Number of neutrons

91. What do you call the space between and around charged bodies?

• A. Magnetic field
• B. Electromagnetic field
• C. Electromotive field
• D. Electrostatic field

92. What electrical quantity is measured by a watt-hour meter?

• A. Current
• B. Energy
• C. Voltage
• D. Power

93. What do you call the process of converting chemical energy into electrical energy in a cell?

• A. Electron flow
• B. Polarization
• C. Electrolysis
• D. Electrochemical action

94. A transformer has 500 turns in the primary and 1500 in the secondary. Assuming no losses, if 45 V is applied to the primary what is the voltage developed in the secondary?

• A. 13.5 V
• B. 180 V
• C. 135 V
• D. 90 V

95. What do you call the maintenance of oscillation in a circuit in the intervals between pulses of excitation energy?

• A. Auto-oscillation
• B. Damping
• C. Flywheel effect
• D. Feedback

96. A 15 µC point charge is located on the y-axis at (0, 0.25). A second charge of 10 µC is located on the x-axis at (0.25, 0). lf the two charges are separated by air, what is the force between them?

• A. 0.0982 N
• B. 0.341 N
• C. 10.79 N
• D. 33.93 N

97. What is energy of motion called?

• A. Potential energy
• B. Kinematics
• C. Pneumatics
• D. Kinetic energy

98. A fully charged lead-acid battery will indicate a specific gravity reading between.

• A. 1.175 to 1.200
• B. 1.200 to 1.225
• C. 1.225 to 1.250
• D. 1.275 to 1.300

99. An effect about microwave oscillation that occurs in a small block of N-type gallium arsenide when a constant DC voltage above a critical value is applied to contact on opposite faces.

• A. Gunn effect
• B. Mossbauer effect
• C. Edison effect
• D. Miller effect

100. What is the most influential factor in the switching speed of saturated bipolar transistor?

• A. Charge storage
• C. hfe
• B. Collector current
• D. hie

Complete List of Electronics Engineering Exams: ECE Pre-Board

Check your work.

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This is 100 items set of Practice Examination 9 in Electronics Engineering composed of previous Board Exams Questions. Read each questions and choices carefully! Choose the best answer. In the actual board, you have to answer 100 items in Electronics Engineering within 5 hours. You have to get at least 70% to pass the subject. Electronics Engineering is 30% of the total 100% Board Rating along with Mathematics (20%), General Engineering and Applied Sciences (20%) and Electronics Systems and Technology (30%).

Start the Test Yourself Exam 9

Choose the letter of the best answer in each questions.

1. What is the maximum number of electrons in a subshell?

• A. 2
• B. 6
• C. 10
• D. 14

2. The repeatability of a servo-controlled robot is within _____ mm rather than a fraction of a mm.

• A. 2
• B. 4
• C. 3
• D. 5

3. What is the principal quantum number of a Q shell?

• A. 6
• B. 5
• C. 4
• D. 7

4. What time when the voltage across L will be equal to the voltage across R in a series RL transient circuit where E = 24 V, R = 10 Ω and L = 1 H?

• A. 69.3 ms
• B. 69.3 s
• C. 6.93 ms
• D. 6.93 s

5. What is the hysteresis loss at a frequency of 60 cycles per second of an audio transformer magnetic core which has a maximum flux density of 10,000 gausses? The volume of solid iron of this core is 66.8 cubic cm and the hysteresis coefficient (a constant that depends upon grade and quality of iron) id 5.35 x 10^-4.

• A. 0.5386 W
• B. 53.86 W
• C. 5.386 W
• D. 5386 W

6. When two coils of equal inductances are connected in series with coefficient of coupling and their fields in phase, find the total inductance of two coils.

• A. 2L_A
• B. 2L_A (1+k)
• C. 2kL_A
• D. L_A (2 + k)

7. A 2 μF capacitor with initial charge q₀ = 100 μC, is connected across a 100 Ω resistor at t = 0. Calculate the time in which the transient voltage across the resistor drops from 40 to 10 V.

• A. 2.77 s
• B. 0.277 ms
• C. 2.77 ms
• C. 0.277 s

8. What do you call a small D.C generator built into alternators to provide excitation current to field windings?

• A. prime mover
• B. excitor
• C. commutator
• D. load

9. What is the condition of the diode in a parallel-limiter when the output is developed?

• A. Shunted
• B. Conducting
• C. Cut-off
• D. Shorted

10. What is the payload of the industrial robot AEA IRb-60?

• A. 60kg
• B. 80kg
• C. 50kg
• D.70kg

11. Which of the following robot is primarily used for machining processes?

• A. Cincinatti T1
• B. Cincinatti T3
• C. Cincinatti T2
• D. Cincinatti T4

12. The Kuka spot welding robot has how many degrees of freedom?

• A. 4
• B. 6
• C. 5
• D.7

13. What system in industrial electronics has the ability to monitor certain variable in the industrial processes, the same can perform self-correcting action?

• A. Coal-slurry system
• B. Closed-loop system
• C. Open-loop system
• D. Feed forward control system

14. What is the property of a gyro so that the axis of rotation or spin axis tends to remain in a fixed direction in space if no force is applied to it?

• A. Selectivity
• B. Precession
• C. Rigidity
• D. Sensitivity

15. In a series RLC circuit with R= 200Ω L= 0.1 H and C= 5µF, find the transient current after the switch is closed at t=0 applying a 200V source.

• A. 2^e-1000tsin 1000t
• B. 2^e-1000tcos 1000t
• C. 2^e-100tsin 100t
• D. 2^e-100tcos 100t

16. A 0.09 µF capacitor is charged to 220V. How long in milliseconds will it discharge to a level of 110V if the discharge resistor has a resistance of 20kΩ?

• A. 1.25
• B. 12.5
• C. 125
• D. 0.125

17. What are the heavy particles that include the proton and the neutron?

• A. Mesons
• B. Baryons
• C. Leptons
• D. Quarks

18. What particles have rest masses ranging down to about 0.1amu?

• A. Leptons
• B. Baryons
• C. Quarks
• D. Mesons

19. By definition, what is the individual angular momentum of the neutron proton and electron?

• A. h/4π
• B. h/2π
• C. h/π
• D. 4πh

20. In the hysteresis loop, what do you call the product of the residual magnetic flux and coercive field strength?

• A. Effectivity product
• B. Hysteresis coefficient
• C. Residual-coercive product
• D. Steinmetz’s product

21. Programming of a continuous-path robot is normally carried out by a method called ______ through.

• A. See
• B. Walk
• C. Pull
• D. Push

22. What do you call the strong magnetism that occurs in certain ceramic compounds such as ferrites?

• A. Ferromagnetism
• B. Ferrimagnetism
• C. Diamagnetism
• D. Paramagnetism

23. What characteristic is determined by the time required for a voltage wave to travel from the input end of an electrical transmission line to the output end and back again?

• A. Pulse position
• B. Pulse line
• C. Pulse width
• D. Pulse code

24. A disturbance similar to brownout but of shorter duration that occurs when the line voltage drops below 80-85% of its rated voltage by one or more cycles.

• A. Sag or dip
• B. Chronic overvoltage
• C. Spike
• D. Transient

25. What term is given to the positions of the rotors of a synchro transmitter and the synchro receiver when both rotors are on a 0 degree displaced from 0 degree by the same angle?

• A. Correspondence
• B. Overlap
• C. Fine tune
• D. Stability

26. What ac voltage defect refers to a high voltage (up to 6000V or more) peak lasting approximately 100µs to one-half cycle?

• A. Sag or dip
• B. Spike
• C. Chronic overvoltage
• D. Transient

27. The largest computers commonly use a word size of ______ bits.

• A. 32
• B. 128
• C. 64
• D. 256

28. What do you call the ratio of the safe load to the nameplate load of an electrical motor?

• A. Service factor
• B. Load factor
• C. Efficiency
• D. Service life

29. Covalent bond energy in germanium is about ____ eV.

• A. 1.5
• B. 7.4
• C. 3.0
• D. 4.7

30. The service factors of motors vary from ____ to _____.

• A. 2.5 to 2.9
• B. 1.15 to 1.4
• C. 1.1 to 1.3
• D. 3.1 to 5.5

31. How many voltage are available from two-phase, three wire alternator?

• A. One
• B. Three
• C. Two
• D. Four

32. At what frequency does the RC circuit of an amplifier reduce the voltage gain to 70.7 percent of its midrange value?

• A. Resonant
• B. Cutoff
• C. Critical
• D. Natural

33. What is the operating temperature of class A motor under motor classification?

• A. 105°C
• B. 130°C
• C. 155°C
• D. 180°C

34. What particular motor class in which the operating temperature is 180°C?

• A. Class H
• B. Class F
• C. Class A
• D. Class B

35. What are the basic components of a harmonic drive used in robot transmission system?

• A. Wave generator
• B. Flexspline
• C. Circular spline
• D. All of the choices

36. What is the operating temperature of class B motor?

• A. 200°C
• B. 155°C
• C. 130°C
• D. 180°C

37. What is the width of the pulse radiated by a fire control tracking radar?

• A. Very thick
• B. Narrow
• C. Thick
• D. Very narrow

38. If the operating temperature is 155°C then it falls under what motor classification?

• A. Class F
• B. Class B
• C. Class H
• D. Class A

39. How much percent is stray losses in dc machines?

• A. 1%
• B. 2%
• C. 5%
• D. 10%

40. What are considered standard minimum distance between components on a chip?

• A. 4 and 5 µm
• B. 5 and 10 µm
• C. 2 and 3 µm
• D. 1 and 2µm

41. For an advanced chip, the minimum distance between components is

• A. 1 µm
• B. 2 µm
• C. 3 µm
• D. 4 µm

42. What are used to apply or remove power and to select a function or a circuit within a device?

• A. Switch
• B. Relay
• C. Circuit control devices
• D. Breaker

43. What do you call a register on the CPU used for the temporary storage of data during arithmetic or logic operations?

• A. Flip-flop
• B. Accumulator
• C. Memory
• D. RAM

44. What parameter specifies the value of voltage from cathode to cathode at which the SCR breaks into the avalanches region and begins to conduct heavily as in the pn junction diode?

• A. Forward-breakover voltage
• B. Reverse-breakover voltage
• C. Break-over voltage
• D. Stop-over voltage

45. What type of servo system based on the same principle of error-signal generation where velocity is sensed, and the load is moving at the desired velocity?

• A. Velocity servo
• B. Rate servo
• C. Speed servo
• D. Controlled servo

46. What is the term for the switch that disconnects the circuit completely at one position before the connection of the next position made?

• A. Break-before-make
• B. Make-before-break
• C. Break-before-break
• D. Make-before-make

47. What is the identifying feature of a colpitts oscillator?

• A. Split inductor
• B. Split resistor
• C. Split transformer
• D. Split capacitor

48. What instrument is used to measure the amount of active ingredients in the electrolyte of a battery?

• A. Hygrometer
• B. Voltmeter
• C. Electrometer
• D. Hydrometer

49. What is the typical frequency range about the center frequency of a tunable magnetron?

• A. ± 5%
• B. ± 2%
• C. ± 4%
• D. ± 6%

50. What is a gaseous tube that uses a poll of liquid mercury at its cathode?

• A. Thyratron
• B. Phanotron
• C. Klystron
• D. Ignitron

51. What is the science of interaction or interconversion of electrical and acoustic phenomena?

• A. Electrodynamics
• B. Electrography
• C. Electroanalysis
• D. Electroacoustics

52. What do you call the graphic record or the curve traced by the electrical activity of the brain as recorded by the electroencephalograph?

• A. Electroform
• B. Electrograph
• C. Electrocardiogram
• D. Electroencephalogram

53. What imaging technique produces clear view of flowing blood or its blockage in narrow vessels?

• A. Blood collation
• B. Chemotography
• C. Blood chemistry
• D. Digital subtraction anglography

54. What tube in a duplexer has the primary function of disconnecting the receiver?

• A. Klystron tube
• B. Magnetron tube
• C. Thyratron tube
• D. TR tube

55. What requirement for a vacuum tube that does not exist for semiconductor?

• A. Filament or heater voltage
• B. Envelope
• C. Grid
• D. Screen

56. An internal component of a klystron oscillator which modulates the velocity of the electrons.

• A. the pair of buncher grids
• B. The pair o f plates
• C. The pair of catcher grids
• D. The collector plate

57. 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?

• A. 17%
• B. 20%
• C. 80%
• D. 83%

58. A 50-µA meter movement has an internal resistance of 2 kΩ. What applied voltage is required to indicate half-scale deflection?

• A. 0.01volt
• B. 0.10volt
• C. 0.005volt
• D. 0.05volt

59. The expression “voltage regulation” as it applies to a shunt-wound DC generator operating at a constant frequency refers to

• A. Voltage output efficiency
• B. Voltage in the secondary compared to the primary
• C. Voltage fluctuations from load to no-load
• D. Rotor winding voltage

60. The expression “voltage regulation” as it applies to a generator operating at a constant frequency refers to

• A. Full load to no load
• B. Limited load to peak load
• C. Source input supply frequency
• D. Field frequency

61. When an emergency transmitter uses 325 watts and a receiver uses 50 watts, how many hours can a 12.6 volt, 55 ampere-hour battery supply full power to both units?

• A. 6hours
• B. 3hours
• C. 1.8hours
• D. 1.2hours

62. What is the total voltage when 12 nickel-cadmium batteries are connected in series?

• A. 12volts
• B. 12.6volts
• C. 15volts
• D. 72volts

63. The turn ratio of a transformer is 1:20. When a 120 volt ac source is connected to its primary winding, the secondary voltage is

• A. 120volts
• B. 1200volts
• C. 600volts
• D. 2400volts

64. A power transformer has a single primary winding and three secondary windings producing 5.0 volts, 12.6 volts, and 150 volts. Which of the three secondary windings will have the highest measured DC resistance

• A. The 12.6 volt winding
• B. The 5.0 volt winding
• C. The 150 volt winding
• D. All will have equal resistance values

65. A special type of power supply filter choke inductance is inversely proportional to the amount of current flowing through it is a

• A. AF choke
• B. RF choke
• C. Smoothing choke
• D. Swinging choke

66. What is the most suitable oscillator circuit for generating 1kHz?

• A. Hartley oscillator
• B. Colpitt’s oscillator
• C. Wien bridge oscillator
• D. Tuned collector oscillator

67. How many the range of a thermocouple ammeter be increased?

• A. By using a current transformer
• B. By using a capacitor shunt
• C. By using a current transformer and a capacitor shunt
• D. By using a resistor shunt

68. By what factor must the voltage of an ac circuit, as indicated on the scale of an ac voltmeter, be multiplied to obtain the average voltage value?

• A. 0.707
• B. 0.9
• C. 1.414
• D. 3.14

69. What special type of diode is capable of both amplification and oscillation?

• A. Point contact diodes
• B. Zener diodes
• C. Tunnel diodes
• D. Junction diodes

70. What is a common use of hot-carrier diode?

• A. As balanced inputs SSB
• B. As a variable capacitance in a automatic frequency control circuit
• C. As a constant voltage reference in a power supply
• D. As VHF and UHF mixers and detectors

71. What is the normal operating voltage and current for a light-emitting diode?

• A. 60 volts and 20 mA
• B. 5 volts and 50 mA
• C. 1.7 volts and 20 mA
• D. 0.7 volts and 60 mA

72. What type of bias is required for an LED to produce luminescence?

• E. Reverse bias
• A. Forward bias
• B. Zero bias
• C. Inductive bias

73. What is the name of the semi-conductor IC that has a fixed pattern of digital data stored in its memory matrix?

• A. RAM—Random-Access Memory
• B. ROM—Read-Only Memory
• C. Register
• D. Latch

74. What would be the bandwidth of a good crystal lattice band-pass filter for a double-sideband phone emission?

• A. 1 kHz at -6 dB
• B. 500 Hz at -6 dB
• C. 6 kHz at -6 dB
• D. 15 kHz at -6 dB

75. What technique can be used to construct low cost, high performance crystal lattice filters?

• A. Splitting and tumbling
• B. Tumbling and grinding
• C. Etching and splitting
• D. Etching and grinding

76. What term defines a series of overshoots in a servo system?

• A. Positioning
• B. Variation
• C. Hunting
• D. Oscillating

77. What is the acceptable ratio of back-to-forward resistance for a diode?

• A. 2 to 1.5
• B. Greater than 10 to 1
• C. Less than 10 to 1
• D. 3 to 2

78. Packaging is required for what reason in IC production?

• A. To meet storage requirement
• B. To increase shelf-life
• C. To dissipate heat
• D. Ease of handling and protection from damage

79. In radioactivity, what is the unit to measure the biological damage caused by radiation?

• A. rem
• B. rad
• C. lumen
• D. reb

80. What do you call the fine wires connecting the bonding pad to the chip t the external lead of the package?

• A. Harness
• B. Cables
• C. Bonding wires
• D. Leads

81. What do you call the ratio between the intensity of magnetization produced in a substance, to the source of magnetizing force?

• A. Magnetic resistivity
• B. Magnetic conductivity
• C. Magnetic susceptibility
• D. Magnetic reluctivity

82. What is a semi-conductor chip with electrodes (leads) extended beyond the wafer?

• A. DICE
• B. Flip chip
• C. Beam-lead chip
• D. DIP

83. What do you call an assembly of microcircuits or a combination of microcircuits and discrete components packaged as replacement?

• A. Electronic module
• B. Microcircuit module
• C. PCB
• D. Minielectronics

84. In the operation of dry cells, we normally refer to the supply of current to load resistance where its current neutralizes the separated charges at the electrodes as ________>.

• A. aligning the cells

• B. charging the cells

• C. discharging the cells

• D. polarizing the cells

85. What are the special class C amplifiers that are biased at 3 to 10 times the normal cutoff and used to generate frequency that is a harmonic of a lower frequency?

• A. Frequency generators
• B. Frequency stabilizers
• C. Frequency multipliers
• D. Frequency amplifiers

86. Which of the following capacitors costs more per µF of capacitance?

• A. Plastic
• B. Mica
• C. Paper
• D. Electrolytic

87. What capacitors are suitable for dc filter circuits?

• A. Mica
• B. Electrolytic
• C. Ceramic
• D. Plastic

88. What is the other name or relative permittivity?

• A. Dielectric strength
• B. Breakdown voltage
• C. Specific inductive capacity
• D. Potential gradient

89. In RF amplifier with optimum coupling, what method provides the widest bandpass?

• A. A parallel circuit
• B. A swamping resistor
• C. A parallel variable resistor
• D. A dc coupling capacitor

90. What is the operating condition of a circuit when no input signal is being applied to the circuit?

• A. Neutral
• B. Quantum
• C. Quiescence
• D. No load condition

91. What is the reading of a fully charged lead-acid battery?

• A. 1.025-1.075
• B. 1.200-1.500
• C. 1.050-1.350
• D. 1.280-1.300

92. Which of the following are the basic elements in a 555 timer IC?

a) Two comparators

b) A flip-flop

c) A discharge transistor

d) A resistive voltage divider

• A. A, B and D only
• B. A, B and C only
• C. B, C and D only
• D. A, B, C and D

93. In a sawtooth generator, increasing gate does what to linearity?

• A. Nothing
• B. Increases linearity
• C. Blocks linearity
• D. Decreases linearity

94. Why are digital multimeters well suited for testing sensitive devices?

• A. High current flow
• B. It is portable and ruggedized
• C. Because of its sensitivity
• D. Current flows through the component is limited to 1 mA

95. Compensation to an op-amp means ________ bandwidth and _________ slew rate.

• A. reduced, increased
• B. reduced, reduced
• C. increased, reduced
• D. increased, increased

96. Boolean algebra is based on the assumption that most quantities have ______ possible states.

• A. four
• B. two
• C. three
• D. single

97. Which of the following are types of resonant LC oscillators?

A. Colpitts

B. Clapp

C. Hartley

D. Armstrong

E. Crystal-controlled

• A. A, B, C and E only
• B. A, B, C and D only
• C. B, C, D and E only
• D. A, B, C, D and E

98. What does the base or radix of a number system tell you about the system?

A. Number of units used in the system

B. Number of items used in the system

C. Number of symbols used in the system

D. Number of numerals used in the system

99. The specific gravity of a lead-acid battery is a measure of its ______

• A. battery life
• B. operating temperature
• C. state of charge
• D. rate of discharge

100. In active filter, what type of filter passes a range of frequency and a certain higher frequency?

• A. Band-stop
• B. High pass
• C. Low pass
• D. Band-pass

Complete List of Electronics Engineering Exams: ECE Pre-Board

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