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
A decoder converts ________.
A. noncoded information into coded form
B. coded information into noncoded form
C. HIGHs to LOWs
D. LOWs to HIGHs
Question 2
Convert the fractional binary number 10010.0100 to decimal.
A. 24.5
B. 18.25
C. 18.4
D. 16.25
Question 3
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 4
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 5
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 6
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 7
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 8
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 9
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 10
How many binary bits are necessary to represent 748 different numbers?
A. 9
B. 7
C. 10
D. 8
Question 11
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 12
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 13
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.
Question 14
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 15
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 16
Convert the fractional binary number 0000.1010 to decimal.
A. 0.625
B. 0.5
C. 0.55
D. 0.1
Question 17
Convert the fractional decimal number 6.75 to binary.
A. 111.11
B. 110.101
C. 110.11
D. 110.011
Question 18
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 19
Give the decimal value of binary 10000110.
A. 13410
B. 14410
C. 11010
D. 12610
Question 20
What is the decimal value of 2–1 ?
A. 0.5
B. 0.25
C. 0.05
D. 0.1
Question 21
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 22
Any number with an exponent of zero is equal to:
A. zero
B. one
C. that number
D. ten
Question 23
Which of the following is not an analog device?
A. Thermocouple
B. Current flow in a circuit
C. Light switch
D. Audio microphone
Question 24
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 25
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 26
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 27
Which format requires fewer conductors?
A. Parallel
B. Serial
C. Both are the same
D. Cannot tell
Question 28
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 29
What kind of logic device or circuit is used to store information?
A. Counter
B. Register
C. Inverter
D. Buffer
Question 30
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 31
How many unique symbols are used in the decimal number system?
A. One
B. Nine
C. Ten
D. Unlimited
Question 32
A type of digital circuit technology that uses bipolar junction transistors is ________.
A. TTL
B. CMOS
C. LSI
D. NMOS
Question 33
Convert the fractional binary number 0001.0010 to decimal.
A. 1.4
B. 1.125
C. 1.2
D. 1.8
Question 34
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 35
The generic array logic (GAL) device is ________.
A. one-time programmable
B. reprogrammable
C. a CMOS device
D. reprogrammable and a CMOS device
Question 36
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 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
PLCC packages have leads on ________.
A. one side
B. two sides
C. three sides
D. four sides
Question 39
Digital signals transmitted on a single conductor (and a ground) must be transmitted in:
A. slow speed.
B. parallel.
C. analog.
D. serial.
Question 40
An encoder converts ________.
A. noncoded information into coded form
B. coded information into noncoded form
C. HIGHs to LOWs
D. LOWs to HIGHs
Question 41
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 42
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 43
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 44
A flip-flop has ________.
A. one stable state
B. no stable states
C. two stable states
D. none of the above
Question 45
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 46
Which format can send several bits of information faster?
A. Parallel
B. Serial
C. Both are the same
D. Cannot tell
Question 47
What is the decimal value of 23 ?
A. 2
B. 4
C. 6
D. 8
Question 48
Give the decimal value of binary 10010.
A. 610
B. 910
C. 1810
D. 2010
Question 49
Any number with an exponent of one is equal to:
A. zero.
B. one.
C. two.
D. that number.
Question 50
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 51
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 52
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 53
Which of the following is a semiconductor memory?
A. RAM
B. MAR
C. CD-ROM
D. CD
Question 54
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.