Digital Concepts MCQs : This section focuses on the "Digital Concepts". These Multiple Choice Questions (MCQs) should be practiced to improve the Digital Concepts skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
What is the decimal value of 23 ?
A. 2
B. 4
C. 6
D. 8
Question 2
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
Question 3
A classification of ICs with complexities of 12 to 100 equivalent gates on a chip is known as ________.
A. SSI
B. MSI
C. LSI
D. VLSI
Question 4
A common instrument used in troubleshooting a digital circuit is a(n) ________.
A. logic probe
B. oscilloscope
C. pulser
D. all of the above
Question 5
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
Question 6
A decoder converts ________.
A. noncoded information into coded form
B. coded information into noncoded form
C. HIGHs to LOWs
D. LOWs to HIGHs
Question 7
A demultiplexer has ________.
A. one data input and a number of selection inputs, and they have several outputs
B. one input and one output
C. several inputs and several outputs
D. several inputs and one output
Question 8
A flip-flop has ________.
A. one stable state
B. no stable states
C. two stable states
D. none of the above
Question 9
A full subtracter circuit requires ________.
A. two inputs and two outputs
B. two inputs and three outputs
C. three inputs and one output
D. three inputs and two outputs
Question 10
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
Question 11
A periodic digital waveform has a pulse width (tw) of 6 ms and a period (T) of 18 ms. The duty cycle is ________.
A. 3.30%
B. 33.30%
C. 6%
D. 18%
Question 12
A pulse has a period of 15 ms. Its frequency is ________.
A. 6.66 Hz
B. 66.66 Hz
C. 666.66 Hz
D. 15 Hz
Question 13
A type of digital circuit technology that uses bipolar junction transistors is ________.
A. TTL
B. CMOS
C. LSI
D. NMOS
Question 14
An encoder converts ________.
A. noncoded information into coded form
B. coded information into noncoded form
C. HIGHs to LOWs
D. LOWs to HIGHs
Question 15
Any number with an exponent of one is equal to:
A. zero.
B. one.
C. two.
D. that number.
Question 16
Any number with an exponent of zero is equal to:
A. zero
B. one
C. that number
D. ten
Question 17
Convert the fractional binary number 0000.1010 to decimal.
A. 0.625
B. 0.5
C. 0.55
D. 0.1
Question 18
Convert the fractional binary number 0001.0010 to decimal.
A. 1.4
B. 1.125
C. 1.2
D. 1.8
Question 19
Convert the fractional binary number 10010.0100 to decimal.
A. 24.5
B. 18.25
C. 18.4
D. 16.25
Question 20
Convert the fractional decimal number 6.75 to binary.
A. 111.11
B. 110.101
C. 110.11
D. 110.011
Question 21
Digital representations of numerical values of quantities may BEST be described as having characteristics:
A. that are difficult to interpret because they are continuously changing.
B. that vary constantly over a continuous range of values.
C. that vary in constant and direct proportion to the values they represent.
D. that vary in discrete steps in proportion to the values they represent.
Question 22
Digital signals transmitted on a single conductor (and a ground) must be transmitted in:
A. slow speed.
B. parallel.
C. analog.
D. serial.
Question 23
Give the decimal value of binary 10000110.
A. 13410
B. 14410
C. 11010
D. 12610
Question 24
Give the decimal value of binary 10010.
A. 610
B. 910
C. 1810
D. 2010
Question 25
How many binary bits are necessary to represent 748 different numbers?
A. 9
B. 7
C. 10
D. 8
Question 26
How many unique symbols are used in the decimal number system?
A. One
B. Nine
C. Ten
D. Unlimited
Question 27
In a certain digital waveform, the period is four times the pulse width. The duty cycle is ________.
A. 0%
B. 25%
C. 50%
D. 100%
Question 28
In positive logic, ________.
A. a HIGH = 1, a LOW = 0
B. a LOW = 1, a HIGH = 0
C. only HIGHs are present
D. only LOWs are present
Question 29
In the decimal numbering system, what is the MSD?
A. The middle digit of a stream of numbers
B. The digit to the right of the decimal point
C. The last digit on the right
D. The digit with the most weight
Question 30
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.
Question 31
PLCC packages have leads on ________.
A. one side
B. two sides
C. three sides
D. four sides
Question 32
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.
Question 33
The frequency of a pulse train is 2 kHz. The pulse period is ________.
A. 5 ms
B. 50 ms
C. 500 s
D. 2 s
Question 34
The generic array logic (GAL) device is ________.
A. one-time programmable
B. reprogrammable
C. a CMOS device
D. reprogrammable and a CMOS device
Question 35
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
Question 36
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
Question 37
The output of an AND gate is LOW ________.
A. all the time
B. when any input is LOW
C. when any input is HIGH
D. when all inputs are HIGH
Question 38
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
Question 39
The parallel transmission of digital data:
A. is much slower than the serial transmission of data.
B. requires only one signal line between sender and receiver.
C. requires as many signal lines between sender and receiver as there are data bits.
D. is less expensive than the serial method of data transmission.
Question 40
The range of voltages between VL(max) and VH(min) are ________.
A. unknown
B. unnecessary
C. unacceptable
D. between 2 V and 5 V
Question 41
The rise time is the time it takes a pulse to go from ________.
A. the base line to the maximum HIGH voltage
B. 10% of the pulse amplitude to the maximum HIGH voltage
C. the base line to 90% of the pulse amplitude
D. 10% of the pulse amplitude to 90% of the pulse amplitude
Question 42
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
Question 43
What has happened to the advances in digital technologies over the past three decades?
A. Slowed down considerably
B. Continued to increase, but at a decreasing rate
C. Made excellent progress
D. Nothing short of phenomenal
Question 44
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.
Question 45
What is an analog-to-digital converter?
A. It makes digital signals.
B. It takes analog signals and puts them in digital format.
C. It allows the use of digital signals in everyday life.
D. It stores information on a CD.
Question 46
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.
Question 47
What is the decimal value of 2–1 ?
A. 0.5
B. 0.25
C. 0.05
D. 0.1
Question 48
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
Question 49
What kind of logic device or circuit is used to store information?
A. Counter
B. Register
C. Inverter
D. Buffer
Question 50
Which format can send several bits of information faster?
A. Parallel
B. Serial
C. Both are the same
D. Cannot tell
Question 51
Which format requires fewer conductors?
A. Parallel
B. Serial
C. Both are the same
D. Cannot tell
Question 52
Which of the following is a semiconductor memory?
A. RAM
B. MAR
C. CD-ROM
D. CD
Question 53
Which of the following is not an analog device?
A. Thermocouple
B. Current flow in a circuit
C. Light switch
D. Audio microphone
Question 54
Which of the following statements does NOT describe an advantage of digital technology?
A. The values may vary over a continuous range.
B. The circuits are less affected by noise.
C. The operation can be programmed.
D. Information storage is easy.