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WorksheetsCombinational Logic circuits
Total questions: 15
Worksheet time: 15mins
Which of the following logic expressions represents the logic diagram shown?
X=AB’+A’B
X=(AB)’+AB
X=(AB)’+A’B’
X=A’B’+AB
The device shown here is most likely a ________
Comparator
Multiplexer
Demultiplexer
Inverter
3 bits full adder contains ________
3 combinational inputs
4 combinational inputs
6 combinational inputs
8 combinational inputs
What is a multiplexer?
It is a type of decoder which decodes several inputs and gives one output
A multiplexer is a device which converts many signals into one
It takes one input and results into many output
It is a type of encoder which decodes several inputs and gives one output
In a multiplexer, the selection of a particular input line is controlled by ___________
Data controller
Selection Lines
Logic Gates
None of above
If the number of n selected input lines is equal to 2^m then it requires _____ select lines.
2
m
n
2n
How many select lines would be required for an 8-line-to-1-line multiplexer?
2
4
8
3
How many NOT gates are required for the construction of a 4-to-1 multiplexer?
3
2
5
4
A combinational circuit is one in which the output depends on the ____________
Input combination at the time
Input combination and the previous output
Input combination at that time and the previous input combination
None of above
Most demultiplexers facilitate which type of conversion?
Decimal to hexadecimal
Single input multiple output
AC to DC
Odd parity to even parity
In 1-to-4 demultiplexer, how many select lines are required?
2
3
4
5
Which IC is used for the implementation of 3-8 DEMUX?
IC74154
IC74155
IC74139
IC74138
The full subtractor can be implemented using ___________
Two XOR and an OR gates
Two half subtractors and an OR gate
Two multiplexers and an AND gate
Two comparators and an AND gate
The output of following BCD addition is:
(1000)BCD+(0100)BCD=
00010010
000011110
000001111
111101000
Which of the following circuits in figure (a to d) is the sum-of-products implementation of figure (e)?
a
b
c
d
