# Electronics Engineering Mastery Test 19: ECE Pre-Board

(Last Updated On: April 4, 2021) This is 100 items set of Practice Examination 19 in Electronics Engineering composed of previous and/or potential 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 4 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 19

Choose the letter of the best answer in each questions.

1. If bandwidth increases, the

a. center frequency decreases

b. Q decreases

c. Roll-off rate increases

d. Ripples appear in the stopband

Solution:

2. The dc output of a bridge type circuit is ____ that of equivalent center-tapped circuit.

a. the same as

b. more than

c. less than

d. none of these

Solution:

3. Which of the following robot drive mechanism is the cheapest to buy but has a limited payload?

a. thermionic

b. hydraulic

c. pneumatic

d. electric

Solution:

4. The output of an OR gate will be low if

a. all inputs are HIGH

b. all inputs are LOW

c. one input is LOW

d. Undetermined

Solution:

5. If a 175-V dc source were connected in series with the utility mains from a standard wall outlet, the result would be

a. smooth dc at a constant voltage

b. pure ac with equal peak voltages

c. ac with one peak voltage greater than the other

d. fluctuating dc

Solution:

6. In constructing transformers, the primary and secondary windings should have

a. good electrical coupling

b. loose magnetic coupling

c. tight magnetic coupling

d. best inductive coupling

Solution:

7. If a sine wave voltage varies from 0-200 V, how much is its instant voltage at 90 degrees?

a. minimum voltage

b. 200 V

c. 100 V

d. half of its maximum voltage

Solution:

8. What is the typical slew rate of Fairchild 741 op-amp?

a. 1 V/μs

b. 10 V/μs

c. 0.5 V/μs

d. 0.333 V/μs

Solution:

9. Small microcomputer used as a dedicated controller for a machine, a piece of equipment, or a process.

a. Microcomputer

b. Microprocessor

c. Microcontroller

d. Supercomputer

Solution:

10. Where do you classify cobalt as material?

a. Non-magnetic

b. Ferromagnetic

c. Paramagnetic

d. Diamagnetic

Solution:

11. If the base-emitter junction is open, the collector voltage is

a. Vcc

b. 0 V

c. floating

d. 0.2 V

Solution:

12. The absolute maximum rating for op-amps interval power dissipation is

a. 500mW

b. 300mW

c. 200mW

d. 100mW

Solution:

13. The power dissipated in the core due to hysteresis and eddy current losses

a. iron loss

b. copper loss

c. winding loss

d. friction loss

Solution:

14. Which of the following is not an internal digital IC fault?

a. open signal lines

b. shorted signal lines

c. faulty power supply

d. poor solder connections

Solution:

15. A diode limiter circuit

a is useful for voltage regulation

b. always uses zener diodes

c. rectifies the audio to reduce distortion

d. can cause objectionable signal distortion

Solution:

16. An elementary generator consists of a single coil rotating in a magnetic field. Why is no voltage induced in the coil as it passes through the neutral plane?

a. Flux lines are too dense

b. Flux lines are not present

c. Flux lines are not being cut

d. Flux lines are being cut in the wrong direction

Solution:

17. A manufacturer quotes in his specifications that a silicon diode conducts 50 mA at 1 V. Determines its bulk resistance.

a.  20 ohms

b. 4 ohms

c. 14 ohms

d. 6 ohms

Solution:

18. A radio equipment will be used to 70% at 50 amperes rating of 5 hours, how much capacity of dry battery is needed?

a. 35

b. 17.5

c. 250

d. 175

Solution:

19. Type of feedback employed in oscillators

a. negative

b. zero

c. positive

d. inductive

Solution:

20. A digital circuit that oscillates between two unstable output states.

a. monostable multivibator

b. astable multivibrator

c. bistable multivibrator

d. flip-flop

Solution:

21. Capacitors are used to store data in

a. timers

b. op amps

c. multiplexers

d. none of these

Solution:

22. The input resistance of a common-base amplifier is

a. very low

b. very high

c. the same as CE

d. the same as CC

Solution:

23. What is the normal resting state of the SET and CLEAR inputs in a NAND gate latch?

a. SET=1, CLEAR=1

b. SET=0, CLEAR=1

c. SET=1, CLEAR=0

d. SET=0, CLEAR=0

Solution:

24. Voltage that is present at the output of an operational amplifier with its two inputs grounded.

a. common-mode signal

b. output offset voltage

c. input offset voltage

d. Ground voltage

Solution:

25. Type of waveform generated by the sweep generator of the CRT.

a. sine wave

b. spike

c. square wave

d. sawtooth

Solution:

26. What are the primary methods of controlling electrical power?

a. by using manual switches and rheostats

b. by using variable reactance and transformers

c. by using electronic  switches, such as diodes, transistors, thyratrons, and thyristors

d. all of these

Solution:

27. Class of programmable logic devices wherein its AND array is programmable while its OR array is hard wired.

a. PAL

b. PLA

c. PLD

d. PROM

Solution:

a. flux times area of the core

b. flux times the number of turns times area of the core

c. flux times number of turns times length of the core

d. flux times number of turns

Solution:

29. The device used to use for rectifying a weak ac signal is a

a. Zener diode

b. Light-emitting diode

c. Varistor

d. Back Diode

Solution:

30. How many NAND-gates are required to form an OR-gate?

a. 2

b. 3

c. 4

d. 5

Solution:

31. What gain is significant when an op-amp is used as a voltage comparator?

a. open-loop gain

b. common voltage gain

c. differential closed loop gain

d. closed loop gain

Solution:

32. Process of repairing the ruptured crystal structure caused by ion implantation by heating.

a. photolithography

b. Czochralski technique

c. diffusion

d. annealing

Solution:

33. Suppose a purely resistive impedance of 75 Ω must be matched to a purely resistive impedance of 300 Ω. A quarter-wave section would need to have

a. Zo = 188 Ω

b. Zo = 150 Ω

c. Zo = 225 Ω

d. Zo = 375 Ω

Solution:

34. How many cells would a 16 word x 6 bit memory contain?

a. 16

b. 96

c. 22

d. 108

Solution:

35. Find the half-power bandwidth of a parallel resonant circuit which has a resonant frequency of 8.1 MHz and Q of 150.

a. 21.1 kHz

b. 47.3 kHz

c. 18.52 kHz

d. 54 kHz

Solution:

36. The purpose of the I layer in a PIN diode is to

a. minimize the diode capacitance

b. optimize the avalanche voltage

c. reduce the forward breakover voltage

d. increase the current through the diode

Solution:

37. The typical saturation flux density for most magnetic materials.

a. 0.1 Wb/m2

b. 2 Wb/m2

c. 10 Wb/m2

d. 20 Wb/m2

Solution:

38. _____ is a measure of consistency of measurements.

a. standards

b. precision

c. accuracy

d. exactness

Solution:

39. A digital computer used for the automation of industrial processes, such as control of machinery or factory assembly lines.

a. microcontroller

b. motor

c. PLC

d. servo

Solution:

40. A JFET always operates with

a. the gate-to-source pn junction reverse-biased

b. the gate-to-source pn junction forward-biased

c. the drain connected to the ground

d. the gate connected to the source

Solution:

41. If Ic is 50 times greater than IB, then βDC is

a. 0.02

b. 100

c. 50

d. 500

Solution:

42. What is the ripple frequency of a half-wave rectifier with an input line frequency of 60 Hz?

a. 30 Hz

b. 60 Hz

c. 90 Hz

d. 120 Hz

Solution:

43. Which of the following amplifiers is considered linear?

a. class A

b. class B

c. class C

d. either class A or B

Solution:

44. Electrical classification of materials having 8 electrons.

a. insulator

b. semiconductor

c. conductor

d. compound

Solution:

45. A full 360°  sine wave signal is applied to an unknown class of amplifier. If the output delivers only a pulse of less than 180° , what class does this amplifier belongs?

a. class AB

b. class B

c. class C

d. class D

Solution:

46. Which of the following is not a general characteristic of an ac wave?

a. the wave shape is identical for each cycle

b. the polarity reverses periodically

c. the electrons always flow in the same direction

d. there is a definite frequency

Solution:

47. A summing amplifier can have

a. No more than two input signals

b. Two or more input signals

c. A closed-loop input impedance of infinity

d. A small open-loop voltage gain

Solution:

48. In an NPN circuit, the collector

a. has an arrow pointing inward

b. is positive with respect to the emitter

c. is biased at a small fraction of the base bias

d. is negative with respect to the emitter

Solution:

49. The bandwidth of a multistage amplifier is _____ that of a single stage amplifier.

a. the same as

b. more than

c. less than

d. either A or B

Solution:

50. A device used to mechanically measure the output power of a motor.

a. dynamometer

b. Megger

c. concentric-vane instrument

Solution:

51. How many major lobes are produced by a paraboloid reflector?

a. one

b. two

c. three

d. four

Solution:

52. The main problem with a bar-graph meter is that:

a. it isn’t very sensitive

b. it isn’t stable

c. it can’t give a very precise reading

d. you need a special training to read it

Solution:

53. What is the maximum efficiency of a full-wave center-tapped rectifier?

a. 50%

b. 40.6%

c. 81.2%

d. 10%

Solution:

54. Which of the following is false, concerning air cores versus ferromagnetic cores?

a. air concentrates the magnetic lines of flux

b. air works at higher frequencies than ferromagnetic

c. ferromagnetic are lossy than air

d. a ferromagnetic core unit needs fewer turns of wire than an equivalent air core unit

Solution:

55. Which statement is wrong regarding μA741 when its supply voltage is increased?

a. open-loop voltage gain will increase

b. increase power consumption

c. maximum voltage swing will increase

d. large variation in the input offset voltage

Solution:

56. If a power supplies 30 V with no load and 20 V under full load, what is the percentage regulation?

a. 33%

b. 66.67%

c. 75%

d. 50%

Solution:

57. Which type of the following oscillator types uses transformer coupling to feed back a portion of the signal voltage. It is sometimes called a “tickler” coil.

a. Hartley circuit

b. Colpitts circuit

c. Clapp circuit

d. Armstrong circuit

Solution:

58. A pulsating dc applied to power amplifiers causes

a. burning of transistor

b. hum in the circuit

c. excessive forward voltage

d. excessive reverse voltage

Solution:

59. In a linear op-amp circuit, the

a. Signals are always sine waves

b. Op-amp does not go into saturation

c. Input impedance is ideally infinite

d. Gain-bandwidth product is constant

Solution:

60. Situation when a circuit’s output level for a given set of input conditions can be assigned as either a 1 or 0.

a. logic 1

b. logic 0

c. latch

d. don’t care

Solution:

61. The regulator with the highest efficiency is the

a. shunt regulator

b. series regulator

c. switching regulator

d. Dc-to-dc converter

Solution:

62. When a closed-loop system is used to maintain physical position it is referred to as

a. gyro system

b. feedback system

c. servo system

d. differential system

Solution:

63. An integrated circuit for both astable and monostable applications.

a. 741 op-amp

b. discrete ICs

c.  Monolithic ICs

d. 555 timer

Solution:

64. Result obtained when a 1 is added to the least significant bit position of a binary number in the 1’s-complement form.

a. 1’s complement

b. 2’s complement

c. 9’s complement

d. 10’s complement

Solution:

65. Low sensitive DC voltmeter provides inaccurate result when measuring ____ circuits.

a. zero resistance

b. high resistance

c. at any resistance

d. low resistance

Solution:

66. Simple current limiting produces too much heat in

a. Zener diode

c. Pass transistor

d. Ambient air

Solution:

67. When an armature opens in dc motor, it may cause

a. intermittent sparking

b. an increase in speed

c. the motor to slow down

d. the motor to stop rotating

Solution:

68. Suppose 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 resistors in series, and connecting these four sets in parallel

b. four sets of two resistors in parallel, and connecting these four sets in series

c. a 3×3 series-parallel matrix of resistors

d. a series-parallel matrix, but something different than those described above.

Solution:

69. A significant advantage, in some situations, of a toroidal coil over a solenoid is the fact that

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

Solution:

70. The input offset current is usually

a. less than the input bias current

b. equal to zero

c. less than the input offset voltage

d. unimportant when a base resistor is used

Solution:

71. Combination of ac motor, dc generator, and exciter to provide adjustable voltage dc power to a dc motor.

a. ward-leonard system

b. half-wave SCR

c. compound generator

d. universal motor

Solution:

72. The ideal internal resistance of an emitter should be

a. equal to the circuit resistance

b. zero

c. infinity

d. higher than circuit resistance

Solution:

73. A frequency synthesizer has

a. high power output

b. high frequency drift rate

c. exceptional stability

Solution:

74. The approximation with a maximally flat passband is

a. Chebyshev

b. Inverse chebyshev

c. Elliptic

d. Bessel

Solution:

75. Electron flow assumes charges flow from

a. negative to positive

b. negative to negative

c. positive to negative

d. positive to ground

Solution:

76. The closed-loop voltage gain of an inverting amplifier equals

a. The ratio of the input resistance to the feedback resistance

b. The open-loop voltage gain

c. The feedback resistance divided by the input impedance

d. The input resistance

Solution:

77. A bubble memory is best suited for:

a. a large computer

b. a home video entertainment system

c. a portable cassette player

d. a magnetic disk

Solution:

78. The operating frequency of a Wien-bridge oscillator is given by _____.

a. 1/(2π√LC)

b. 1/(2πRC)

c. 1/(4πLC)

d. 1/(29RC)

Solution:

79. In an LC oscillator, if the value of L is increased four times, then frequency of oscillations is ____.

a. decreased two times

b. increased two times

c. decreased four times

d. increased four times

Solution:

80. This type of electrical machine is used for varying the input voltage into a higher or lower potential without changing the power transferred.

a. motor

b. generator

c. transformer

d. alternator

Solution:

81. Amplifier of low-level signals that provides an output that is an accurate multiple of the difference between two input signals.

a. Schmitt trigger

b. instrumentation amplifiers

c.  level detector

d. integrator

Solution:

82. Which of the following is not a characteristic of CMOS chips?

a. sensitivity to damage by electrostatic discharge

b. low current demand

c. ability to work at high speed

d. ability to handle extremely high power

Solution:

83. How are the networks able to transform one impedance to another?

a. The matching network introduces transconductance to cancel the resistive part of impedance.

b. Resistance in the networks substitute for the resistances in the load.

c. The matching network introduces negative resistance to cancel the resistive part of an impedance.

d. The matching network can cancel the reactive part of an impedance and change the value of the resistive part of an impedance.

Solution:

84. Power source that converts desired electricity to the other.

a. motor set

b. motor-generator set

c. voltage regulator

d. power regulator

Solution:

85. It is a robot structure wherein the body can pivot vertically and horizontally and that arms move radially.

a. polar structure

b. pivotal

c. cylindrical structure

d. roborat

Solution:

86. How do you determine if diode is effective?

a. diode resistance is either very high or very low in either direction

b. high current

c. very low current

d. high voltage

Solution:

87. The energy of an oscillator can be sourced by

a. coupling a small coil close to the tube

b. capacitance of inductive coupling from the tuned circuit

c. Inserting resistor in grid circuit

d. connecting capacitor across the supply

Solution:

88. 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

Solution:

89. An AC bridge that measures inductance in terms of resistance and capacitance.

a. Owen’s bridge

b. Murray loop

c. Schering bridge

d. Kelvin bridge

Solution:

90. A monopulse receiver has how many separate channels?

a. one

b. two

c. three

d. four

Solution:

91. A meter when _____ damped will become insensitive to small signals.

a. underdamped

b. overdamped

c. critically damped

d. negatively damped

Solution:

92. In a linear regulator, the control transistor is conducting

a. a small part of the time

b. all of the time

c. only when the input voltage exceeds a limit

d. only when there is an overload

Solution:

93. Each stage of a four-stage amplifier has a voltage gain of 15. The overall voltage gain is

a. 60

b. 15

c. 50,625

d. 3078

Solution:

94. With respect to memory, which of the following terms means that the data contents vanish if power is removed from a chip?

a. volatility

b. component density

c. multiplexing

d. corruptibility

Solution:

95. What is the purpose of the emitter capacitor?

a. to forward bias the emitter

b. to reduce noise in the amplifier

c. to avoid drop in gain

d. to stabilize emitter voltage

Solution:

96. The number of digits used by a number system.

a. digits

c. 2n

d. n

Solution:

97. A Schmitt trigger is used to provide

a. A short duration pulse

b. A long duration pulse

c. a digitally compatible output

d. All of these

Solution:

98. One of the following items below is not one of the main components of an alternating current power supply.

a. power transformer

b. Filter

c. Voltage regulator

d. Rectifier

Solution:

99. What are the two basic categories of industrial robots?

a. autobots and deceptions

b. mechanical and electrical

c. fast and slow

d. pick and place manipulator and intelligent robot

Solution:

100. What direction is the magnetic field about a conductor when current is flowing?

a. in a direction opposite to the current flow

b. in all direction, omnidirectional

c. in the same direction of the current

d. in a direction determined by the left hand rule

Solution:

### Complete List of Electronics Engineering Pre-Board Exams

Electronics Engineering Pre-Board Exams
Module 1: Electronics Engineering Exam 1                   Answer key: EXAM 1
Module 2: Electronics Engineering Exam 2                   Answer key: EXAM 2
Module 3: Electronics Engineering Exam 3                   Answer key: EXAM 3
Module 4: Electronics Engineering Exam 4                   Answer key: EXAM 4
Module 5: Electronics Engineering Exam 5                   Answer key: EXAM 5
Module 6: Electronics Engineering Exam 6                   Answer key: EXAM 6
Module 7: Electronics Engineering Exam 7                   Answer key: EXAM 7
Module 8: Electronics Engineering Exam 8                   Answer key: EXAM 8
Module 9: Electronics Engineering Exam 9                   Answer key: EXAM 9
Module 10: Electronics Engineering Exam 10                   Answer key: EXAM 10