Explore topic-wise MCQs in Engineering.

This section includes 2291 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.

101.

The family of logic that is composed of bipolar junction transistors is ____.
A. TTL
B. CMOS
C. DIP
D. BJT
Answer» B. CMOS
Discussion
102.

What can a relay provide between the triggering source and the output that semiconductor switching devices cannot?
A. total isolation
B. faster
C. higher current rating
D. total isolation and higher current rating
Answer» E.
Discussion
103.

Why is parallel data transmission preferred over serial data transmission for most applications?
A. It is much slower.
B. It is cheaper.
C. More people use it.
D. It is much faster.
Answer» E.
Discussion
104.

Which device(s) have almost ideal ON and OFF resistances?
A. electromechanical relays
B. manual switches
C. semiconductor devices (diodes and transistors)
D. electromechanical relays and manual switches
Answer» E.
Discussion
105.

A diode placed in parallel across a relay coil serves what function?
A. to regulate input voltage
B. to protect the coil from arcing
C. to ensure most of the current passes through the coil
D. to reduce arcing across the relay contacts
Answer» C. to ensure most of the current passes through the coil
Discussion
106.

What is the output voltage from the circuit in the given figure?
A. +15 V
B. +12 V
C. +3 V
D. 0 V
Answer» E.
Discussion
107.

The following waveform pattern is for a(n) ________.
A. 2-input AND gate
B. 2-input OR gate
C. Exclusive-OR gate
D. None of the above
Answer» C. Exclusive-OR gate
Discussion
108.

Implementing the expression with NOR logic, we get:
A. (A)
B. (B)
C. (C)
D. (D)
Answer» B. (B)
Discussion
109.

A 4-variable AND-OR-Invert circuit produces a 0 at its Y output. Which combination of inputs is correct?
A. <img src="/_files/images/digital-electronics/digital-fundamentals/mca5_0040a.gif">
B. <img src="/_files/images/digital-electronics/digital-fundamentals/mca5_0040b.gif">
C. <img src="/_files/images/digital-electronics/digital-fundamentals/mca5_0040c.gif">
D. none of the above
Answer» D. none of the above
Discussion
110.

To implement the expression , it takes one OR gate and ________.
A. three AND gates and three inverters
B. three AND gates and four inverters
C. three AND gates
D. one AND gate
Answer» B. three AND gates and four inverters
Discussion
111.

Internally, a computer's binary data are almost always transmitted on parallel channels, commonly referred to as the:
A. parallel bus
B. serial bus
C. data bus
D. memory bus
Answer» D. memory bus
Discussion
112.

Why does the TTL family use a totem-pole circuit on the output?
A. It provides active pull-up.
B. It provides active pull-down.
C. It provides active pull-up and active pull-down.
Answer» D.
Discussion
113.

What is the frequency of a clock waveform if the period of that waveform is
1.25 s?
A. 8 kHz
B. 0.8 kHz
C. 0.8 MHz
D. 8 MHz
Answer» D. 8 MHz
Discussion
114.

Why is the given circuit called an inverter?
A. The output is the opposite (inverse) of the input.
B. The output is in phase with the input.
C. The output is the same as the input.
D. There is no output.
Answer» B. The output is in phase with the input.
Discussion
115.

The output of an exclusive-NOR gate is 1. Which input combination is correct?
A. A = 1, B = 0
B. A = 0, B = 1
C. A = 0, B = 0
D. none of the above
Answer» D. none of the above
Discussion
116.

Is the transistor in the given figure considered ON or OFF?
A. OFF
B. ON
C. Not enough information is provided.
Answer» B. ON
Discussion
117.

Implementation of the Boolean expression results in ________.
A. three AND gates, one OR gate
B. three AND gates, one NOT gate, one OR gate
C. three AND gates, one NOT gate, three OR gates
D. three AND gates, three OR gates
Answer» C. three AND gates, one NOT gate, three OR gates
Discussion
118.

One possible output expression for an AND-OR-Invert circuit having one AND gate with inputs A, B, and C and one AND gate with inputs D and E is ________.
A. <img src="/_files/images/digital-electronics/digital-fundamentals/mca5_0190a.gif">
B. <img src="/_files/images/digital-electronics/digital-fundamentals/mca5_0190b.gif">
C. <img src="/_files/images/digital-electronics/digital-fundamentals/mca5_0190c.gif">
D. <img src="/_files/images/digital-electronics/digital-fundamentals/mca5_0190d.gif">
Answer» D. <img src="/_files/images/digital-electronics/digital-fundamentals/mca5_0190d.gif">
Discussion
119.

A 4-variable AND-OR circuit produces a 0 at its Y output. Which combination of inputs is correct?
A. A = 0, B = 0, C = 1, D = 1
B. A = 1, B = 1, C = 0, D = 0
C. A = 1, B = 1, C = 1, D = 1
D. A = 1, B = 0, C = 1, D = 0
Answer» E.
Discussion
120.

The abbreviation NO, when used with respect to electromechanical relays, stands for not operational.
A. True
B. False
Answer» C.
Discussion
121.

The units for the HIGH time for a periodic wave are ________.
A. seconds
B. hertz
C. cycles
D. %
Answer» B. hertz
Discussion
122.

What is the advantage of using serial data transmission over parallel data transmission?
A. It is slower.
B. Only one pair of wires is required.
C. More people use it.
D. It is faster.
Answer» C. More people use it.
Discussion
123.

Normal operation of an NPN bipolar transistor requires the base to be ________ with respect to the emitter, and ________ with respect to the collector.
A. positive, negative
B. positive, positive
C. negative, positive
D. negative, negative
Answer» B. positive, positive
Discussion
124.

A logic circuit with an output consists of ________.
A. two AND gates, two OR gates, two inverters
B. three AND gates, two OR gates, one inverter
C. two AND gates, one OR gate, two inverters
D. two AND gates, one OR gate
Answer» D. two AND gates, one OR gate
Discussion
125.

Implementing the expression using NAND logic, we get:

A. (A)
B. (B)
C. (C)
D. (D)
Answer» E.
Discussion
126.

Implementing the expression using NAND logic, we get:
A. (A)
B. (B)
C. (C)
D. (D)
Answer» C. (C)
Discussion
127.

What is the advantage of using CMOS logic over TTL?
A. It switches faster.
B. It uses less power.
C. It is larger.
D. cost
Answer» C. It is larger.
Discussion
128.

What is used to graphically show the time relationship between two or more digital waveforms?
A. reference diagram
B. timing diagram
C. voltage curve
D. load line
Answer» C. voltage curve
Discussion
129.

The period of a waveform is the percentage of time the signal is HIGH.
A. True
B. False
Answer» C.
Discussion
130.

Any number with an exponent of zero is equal to:
A. zero
B. one
C. that number
D. ten
Answer» C. that number
Discussion
131.

Parallel format means that:
A. each digital signal has its own conductor.
B. several digital signals are sent on each conductor.
C. both binary and hexadecimal can be used.
D. no clock is needed.
Answer» B. several digital signals are sent on each conductor.
Discussion
132.

The output of a NOT gate is HIGH when ________.
A. the input is LOW
B. the input is HIGH
C. the input changes from LOW to HIGH
D. voltage is removed from the gate
Answer» B. the input is HIGH
Discussion
133.

A DAC changes ________.
A. an analog signal into digital data
B. digital data into an analog signal
C. digital data into an amplified signal
D. none of the above
Answer» C. digital data into an amplified signal
Discussion
134.

A decoder converts ________.
A. noncoded information into coded form
B. coded information into noncoded form
C. HIGHs to LOWs
D. LOWs to HIGHs
Answer» C. HIGHs to LOWs
Discussion
135.

The output of an OR gate is LOW when ________.
A. all inputs are LOW
B. any input is LOW
C. any input is HIGH
D. all inputs are HIGH
Answer» B. any input is LOW
Discussion
136.

What is a digital-to-analog converter?
A. It takes the digital information from an audio CD and converts it to a usable form.
B. It allows the use of cheaper analog techniques, which are always simpler.
C. It stores digital data on a hard drive.
D. It converts direct current to alternating current.
Answer» B. It allows the use of cheaper analog techniques, which are always simpler.
Discussion
137.

What are the symbols used to represent digits in the binary number system?
A. 0,1
B. 0,1,2
C. 0 through 8
D. 1,2
Answer» B. 0,1,2
Discussion
138.

A periodic digital waveform has a pulse width (tw) of 6 ms and a period (T) of 18 ms. The duty cycle is ________.
A. 3.3%
B. 33.3%
C. 6%
D. 18%
Answer» C. 6%
Discussion
139.

Serial format means digital signals are:
A. sent over many conductors simultaneously.
B. sent over one conductor sequentially.
C. sent in groups of eight signals.
D. sent in binary coded decimal.
Answer» C. sent in groups of eight signals.
Discussion
140.

Any number with an exponent of one is equal to:
A. zero.
B. one.
C. two.
D. that number.
Answer» E.
Discussion
141.

Which of the following is a semiconductor memory?
A. RAM
B. MAR
C. CD-ROM
D. CD
Answer» B. MAR
Discussion
142.

The holes through a PC board are ________.
A. smaller with SMT than with through-hole mounting
B. larger with SMT than with through-hole mounting
C. the same size as with through-hole mounting
D. usually unnecessary
Answer» D. usually unnecessary
Discussion
143.

A classification of ICs with complexities of 100 to 10,000 equivalent gates per chip is known as ________.
A. SSI
B. MSI
C. LSI
D. VLSI
Answer» D. VLSI
Discussion
144.

What is the decimal value of 2 1 ?
A. 0.5
B. 0.25
C. 0.05
D. 0.1
Answer» B. 0.25
Discussion
145.

How many unique symbols are used in the decimal number system?
A. One
B. Nine
C. Ten
D. Unlimited
Answer» D. Unlimited
Discussion
146.

What kind of logic device or circuit is used to store information?
A. Counter
B. Register
C. Inverter
D. Buffer
Answer» C. Inverter
Discussion
147.

A multiplexer has ________.
A. one input and several outputs
B. one input and one output
C. several inputs and several outputs
D. several inputs and one output
Answer» E.
Discussion
148.

What is the typical invalid voltage for a binary signal?
A. 0.7 2.8 volts
B. 0.8 3 volts
C. 0.8 2 volts
D. 0.7 2.5 volts
Answer» D. 0.7 2.5 volts
Discussion
149.

What is one relative disadvantage of serial transfer?
A. It requires too many conductors.
B. Its interconnect system is complex.
C. It is slow.
D. It can only be used over very short distances.
Answer» D. It can only be used over very short distances.
Discussion
150.

PLCC packages have leads on ________.
A. one side
B. two sides
C. three sides
D. four sides
Answer» E.
Discussion