2291 + Mcqs in Digital Electronics Page 21 McqOptions

1001.	The full-step sequence of a stepper motor always has two coils energized in any state of the sequence and typically causes ________ of shaft rotation per step.
A.	5
B.	10
C.	15
D.	20
Answer» D. 20

Discussion

1002.	The bistable multivibrator is an R-C flip-flop.
A.	True
B.	False
Answer» C.

Discussion

1003.	When the 74123, a retriggerable monostable multivibrator device, ends its timing cycle it must be started all over again.
A.	True
B.	False
Answer» C.

Discussion

1004.	Timing accuracy of more than eight significant digits can be easily achieved by using quartz crystals.
A.	True
B.	False
Answer» C.

Discussion

1005.	A multivibrator is a circuit that changes between two digital levels on a continuous, free-running basis or on demand.
A.	True
B.	False
Answer» B. False

Discussion

1006.	Depending on the ________ the IC is in, the output of the stepper motor HDL will respond to each pulse by changing state.
A.	mode
B.	make
C.	input
D.	output
Answer» B. make

Discussion

1007.	The step rate of the simulation of a stepper motor is probably ________ the actual stepper motor.
A.	slower than
B.	more than
C.	almost the same as
D.	exactly the same as
Answer» B. more than

Discussion

1008.	One of the first steps in small-project management is to determine ________.
A.	how many devices are controlled by the outputs
B.	a way to test each block
C.	if each block fits together
D.	how each block works
Answer» B. a way to test each block

Discussion

1009.	In the digital clock project, when it is 11:59:59, AND gate 1 detects that the tens of hours is 1 and the enable input is active. On the next clock pulse the AM/PM flip-flop will ________.
A.	set
B.	reset
C.	toggle
D.	clear
Answer» D. clear

Discussion

1010.	In the frequency counter, the control clock is derived from the ________ by frequency dividers controlled in the control and timing block.
A.	BCD counters
B.	system clock signal
C.	display register
D.	decoder/display
Answer» C. display register

Discussion

1011.	Using one case construct inside another is known as ________.
A.	doping
B.	functioning
C.	freezing
D.	nesting
Answer» E.

Discussion

1012.	In the frequency counter, the length of time for the ________ to be enabled can be selected with the range select input.
A.	display register
B.	frequency prescaler
C.	BCD counter
D.	signal generator
Answer» D. signal generator

Discussion

1013.	One aspect of project planning and management is the selection of ________ that will best fit the application.
A.	hardware platform
B.	software
C.	personnel
D.	time
Answer» B. software

Discussion

1014.	VARIABLES are considered to be updated ________ within a sequence of statements in a PROCESS, whereas SIGNALS referred to in a PROCESS are updated when the PROCESS ________.
A.	once, starts
B.	immediately, suspends
C.	twice, ends
D.	never, starts
Answer» C. twice, ends

Discussion

1015.	In the keypad encoder, the ring counter is implemented using ________ that responds to the clk input.
A.	SIGNAL
B.	FUNCTION
C.	CASE
D.	PROCESS
Answer» E.

Discussion

1016.	The major blocks of the frequency counter are the counter, ________, decoder/display, and the timing and control unit.
A.	signal prescaler
B.	control inputs
C.	signal generator
D.	display register
Answer» E.

Discussion

1017.	A byte has 8 bits.
A.	True
B.	False
Answer» B. False

Discussion

1018.	A variable is a symbol used to represent a logical quantity that can have a value of 1 or 0.
A.	True
B.	False
Answer» B. False

Discussion

1019.	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.
Answer» C. It allows the use of digital signals in everyday life.

Discussion

1020.	A very critical dimension in project management is ________.
A.	cost
B.	skill
C.	time
D.	personnel
Answer» D. personnel

Discussion

1021.	The controls on an oscilloscope that will help obtain a stable display are in the ________.
A.	vertical section
B.	horizontal section
C.	trigger section
D.	display section
Answer» D. display section

Discussion

1022.	In the digital clock design, the hours section is different from the seconds and minutes section in that it never goes to ________.
A.	the 0 state
B.	13
C.	the ring counter
D.	the BCD counter
Answer» B. 13

Discussion

1023.	Hex is often used in digital applications as a shorthand way to represent strings of bits.
A.	True
B.	False
Answer» B. False

Discussion

1024.	TTL requires a constant supply voltage of 8.0 V.
A.	True
B.	False
Answer» C.

Discussion

1025.	There is no way to eliminate the effects of a switch bounce.
A.	True
B.	False
Answer» C.

Discussion

1026.	Pull-up resistors and pull-down resistors are used to keep a floating terminal HIGH.
A.	True
B.	False
Answer» C.

Discussion

1027.	A transfer function graph illustrates the most important specifications for the Schmitt trigger devices.
A.	True
B.	False
Answer» B. False

Discussion

1028.	The input levels to a flip-flop must be maintained for a minimum time period both before and after the edge of the clock signal is applied.
A.	True
B.	False
Answer» B. False

Discussion

1029.	The Boolean expression C + CD is equal to ________.
A.	C
B.	D
C.	C + D
D.	1
Answer» B. D

Discussion

1030.	The horizontal axis of an oscilloscope is normally calibrated in units of ________.
A.	voltage
B.	current
C.	time
D.	frequency
Answer» D. frequency

Discussion

1031.	Which of the following combinations cannot be combined into K-map groups?
A.	Corners in the same row
B.	Corners in the same column
C.	Diagonal corners
D.	Overlapping combinations
Answer» D. Overlapping combinations

Discussion

1032.	When extremely critical timing is required, a quartz crystal can be used.
A.	True
B.	False
Answer» B. False

Discussion

1033.	In the 74121, which is nonretriggerable, any triggers that come in before the end of the timing cycle are ignored.
A.	True
B.	False
Answer» B. False

Discussion

1034.	A comparator simply outputs a HIGH or LOW based on a comparison of the voltage levels at its input.
A.	True
B.	False
Answer» B. False

Discussion

1035.	The 74S124 TTL chip is a voltage-controlled oscillator that will generate a specific frequency at Vout.
A.	True
B.	False
Answer» C.

Discussion

1036.	The given figure is most likely a ________.
A.	register
B.	decoder
C.	counter
D.	multiplexer
Answer» B. decoder

Discussion

1037.	If an active-HIGH S-R latch has a 0 on the S input and a 1 on the R input and then the R input goes to 0, the latch will be ________.
A.	SET
B.	RESET
C.	clear
D.	invalid
Answer» C. clear

Discussion

1038.	Most computers store binary data in groups of 32 bits called Dwords.
A.	True
B.	False
Answer» C.

Discussion

1039.	A frequency counter ________ a signal.
A.	measures
B.	displays
C.	measures and displays
D.	measures, displays, and generates
Answer» D. measures, displays, and generates

Discussion

1040.	The terminal marked A on the CTR block in the given figure is the SET terminal.
A.	True
B.	False
Answer» C.

Discussion

1041.	The Boolean sum of the four product terms is called the sum-of-products.
A.	True
B.	False
Answer» B. False

Discussion

1042.	The ________ is the most popular standard logic device family today.
A.	TTL
B.	CMOS
C.	ECL
D.	None of the above
Answer» C. ECL

Discussion

1043.	RAMs must have a input, in addition to data in.
A.	True
B.	False
Answer» B. False

Discussion

1044.	Polling is the process of pausing the normal sequence of instructions to cause the processor to execute a separate set of I/O instructions instead.
A.	True
B.	False
Answer» C.

Discussion

1045.	The most widespread application of ROMs is in the storage of data and program codes that must be available on power-down in the microprocessor-based systems. These data and program codes are called firmware because they are firmly stored in hardware.
A.	True
B.	False
Answer» C.

Discussion

1046.	If [A] = 1011 1010, [B] = 0011 0110, and [C] = [A] [B], what is [C 4..2] in decimal?
A.	1
B.	2
C.	3
D.	4
Answer» E.

Discussion

1047.	Refer to the display multiplexer given below. The MSD display is blank, while the LSD seems to be OK. The input and output lines to the 74157 and 7449 are checked with a scope and can be seen changing levels. The A input on the 74139 also changes; however, the 0 output on the 74139 is always LOW and the 1 output is always HIGH. The B and EN inputs on the 74139 are always LOW. What could cause the problem and what should be done to correct it?
A.	The 74139 is defective; replace it.
B.	The EN pin on the 74139 could have a bad connection; check the connection.
C.	The 74139 is defective and must be replaced; or the EN pin on the 74139 could have a bad connection, which should be checked.
D.	The MSD display is bad; replace it.
Answer» D. The MSD display is bad; replace it.

Discussion

1048.	In order to select data input I5 of a 74151 eight-line multiplexer, the select inputs must be ________.
A.	<img src="/_files/images/digital-electronics/digital-systems/fba9_1023a1.gif">
B.	<img src="/_files/images/digital-electronics/digital-systems/fba9_1023b1.gif">
C.	<img src="/_files/images/digital-electronics/digital-systems/fba9_1023c1.gif">
D.	<img src="/_files/images/digital-electronics/digital-systems/fba9_1023d1.gif">
Answer» B. <img src="/_files/images/digital-electronics/digital-systems/fba9_1023b1.gif">

Discussion

1049.	In the keypad HDL encoder, as long as all columns are high the ring counter is enabled and counting.
A.	True
B.	False
Answer» B. False

Discussion

1050.	Which of the following characterizes an analog quantity?
A.	Discrete levels represent changes in a quantity.
B.	Its values follow a logarithmic curve.
C.	It can be described with a finite number of steps.
D.	It has a continuous set of values over a given range.
Answer» E.

Discussion

Explore topic-wise MCQs in Engineering.

The full-step sequence of a stepper motor always has two coils energized in any state of the sequence and typically causes ________ of shaft rotation per step.

The bistable multivibrator is an R-C flip-flop.

When the 74123, a retriggerable monostable multivibrator device, ends its timing cycle it must be started all over again.

Timing accuracy of more than eight significant digits can be easily achieved by using quartz crystals.

A multivibrator is a circuit that changes between two digital levels on a continuous, free-running basis or on demand.

Depending on the ________ the IC is in, the output of the stepper motor HDL will respond to each pulse by changing state.

The step rate of the simulation of a stepper motor is probably ________ the actual stepper motor.

One of the first steps in small-project management is to determine ________.

In the digital clock project, when it is 11:59:59, AND gate 1 detects that the tens of hours is 1 and the enable input is active. On the next clock pulse the AM/PM flip-flop will ________.

In the frequency counter, the control clock is derived from the ________ by frequency dividers controlled in the control and timing block.

Using one case construct inside another is known as ________.

In the frequency counter, the length of time for the ________ to be enabled can be selected with the range select input.

One aspect of project planning and management is the selection of ________ that will best fit the application.

VARIABLES are considered to be updated ________ within a sequence of statements in a PROCESS, whereas SIGNALS referred to in a PROCESS are updated when the PROCESS ________.

In the keypad encoder, the ring counter is implemented using ________ that responds to the clk input.

The major blocks of the frequency counter are the counter, ________, decoder/display, and the timing and control unit.

A byte has 8 bits.

A variable is a symbol used to represent a logical quantity that can have a value of 1 or 0.

What is an analog-to-digital converter?

A very critical dimension in project management is ________.

The controls on an oscilloscope that will help obtain a stable display are in the ________.

In the digital clock design, the hours section is different from the seconds and minutes section in that it never goes to ________.

Hex is often used in digital applications as a shorthand way to represent strings of bits.

TTL requires a constant supply voltage of 8.0 V.

There is no way to eliminate the effects of a switch bounce.

Pull-up resistors and pull-down resistors are used to keep a floating terminal HIGH.

A transfer function graph illustrates the most important specifications for the Schmitt trigger devices.

The input levels to a flip-flop must be maintained for a minimum time period both before and after the edge of the clock signal is applied.

The Boolean expression C + CD is equal to ________.

The horizontal axis of an oscilloscope is normally calibrated in units of ________.

Which of the following combinations cannot be combined into K-map groups?

When extremely critical timing is required, a quartz crystal can be used.

In the 74121, which is nonretriggerable, any triggers that come in before the end of the timing cycle are ignored.

A comparator simply outputs a HIGH or LOW based on a comparison of the voltage levels at its input.

The 74S124 TTL chip is a voltage-controlled oscillator that will generate a specific frequency at Vout.

The given figure is most likely a ________.

If an active-HIGH S-R latch has a 0 on the S input and a 1 on the R input and then the R input goes to 0, the latch will be ________.

Most computers store binary data in groups of 32 bits called Dwords.

A frequency counter ________ a signal.

The terminal marked A on the CTR block in the given figure is the SET terminal.

The Boolean sum of the four product terms is called the sum-of-products.

The ________ is the most popular standard logic device family today.

RAMs must have a input, in addition to data in.

Polling is the process of pausing the normal sequence of instructions to cause the processor to execute a separate set of I/O instructions instead.

The most widespread application of ROMs is in the storage of data and program codes that must be available on power-down in the microprocessor-based systems. These data and program codes are called firmware because they are firmly stored in hardware.

If [A] = 1011 1010, [B] = 0011 0110, and [C] = [A] [B], what is [C 4..2] in decimal?

In order to select data input I5 of a 74151 eight-line multiplexer, the select inputs must be ________.

In the keypad HDL encoder, as long as all columns are high the ring counter is enabled and counting.

Which of the following characterizes an analog quantity?

VARIABLES are considered to be updated within a sequence of statements in a PROCESS, whereas SIGNALS referred to in a PROCESS are updated when the PROCESS .