Free Printable COMBINATIONAL DIGITAL CIRCUITS

1.

Which of the circuits in figure (a to d) is the sum-of-products implementation of figure (e)?

a)

a

b)

b

c)

c

d)

d

2.

Which of the following logic expressions represents the logic diagram shown?

a)

X=AB’+A’B

b)

X=(AB)’+AB

c)

X=(AB)’+A’B’

d)

X=A’B’+AB

3.

The device shown here is most likely a ________

a)

Comparator

b)

Demultiplexer

c)

Inverter

d)

Multiplexer

4.

What type of logic circuit is represented by the figure shown below?

a)

EX-NOR

b)

EX-OR

c)

NAND

d)

AND

5.

For the device shown here, assume the D input is LOW, both S inputs are LOW and the input is LOW. What is the status of the Y’ outputs?

a)

All are HIGH

b)

All are LOW

c)

All but Y0 are LOW

d)

All but Y0 are HIGH

6.

3 bits full adder contains ________

a)

3 combinational inputs

b)

4 combinational inputs

c)

6 combinational inputs

d)

8 combinational inputs

7.

Represent a decimal number 39 in BCD

(a)

8.

The BCD number 101011 has _______ priority.

a)

Even

b)

Odd

c)

Both even and odd

d)

Undefined

9.

Which gates are ideal for checking the parity bits?

a)

AND

b)

EX-NOR

c)

EX-OR

d)

NAND

10.

What is the radix of hexadecimal number?

a)

15

b)

10

c)

16

d)

2

11.

Convert the binary number 01011 into decimal

a)

10

b)

11

c)

13

d)

12

12.

The number 5A6D belongs to which category of number system

a)

Octal

b)

Hexadecimal

c)

Binary

d)

DEcimal

13.

The number 15 is represented as ............in Hexadecimal.

a)

C

b)

E

c)

F

d)

D

14.

Examples of combinational ckts are

a)

flipflops

b)

adders, mux, demux

c)

both a and b

15.

Design a combinational circuit with three inputs and one output. The output is 1 when the binary value of the inputs is less than 3. The output is 0 otherwise.

a)

F = x'y' + x'z

b)

F = x'y + x'z

c)

F = x'y' + xz

d)

F = x'y' + x'z'

16.

What value is input B, if output Y is high when both input A and input C are high.

a)

Low (0)

b)

High (1)

c)

High impedance

d)

Short-circuit

17.

How many Full adders are needed to design a 6 bit parallel adder?

a)

7

b)

3

c)

6

d)

4

18.

Simplified expression of half adder carry is

a)

c=xy+x

b)

c=y+x

c)

c=xy+y

d)

c=xy

19.

A NOT gate has…

a)

Two inputs and one output

b)

One input and one output

c)

One input and two outputs

d)

Two inputs and two outputs

20.

A logic state can only be….

a)

On or 1

b)

Off or 1

c)

1 or 0

d)

In and Out

21.

What gate is this table for?

a)

AND

b)

OR

c)

NOT

d)

NOR

22.

Which of the following is not a basic gate?

a)

AND

b)

OR

c)

EXOR

d)

NOT

23.

Full adder circuit can perform the addition of ____ bit numbers

a)

3

b)

1

c)

2

d)

4

24.

Multiplexer is a ____ logic circuit

a)

Combinational

b)

Sequential

c)

Random

d)

Memory

25.

( A + B ) ( C + D )

is the same as

a)

AC + BD

b)

(A . B ) + ( C . D )

c)

A + B + C + D

d)

AC + AD + BC + BD

26.

A . ( B + C )
is the same as

a)

___________
A + B + C

b)

( A + B ) ( A + C)

c)

A . B . C

d)

( A . B ) + ( A . C )

27.

Design procedure of combinational circuit involves

a)

4 steps

b)

5 steps

c)

6 steps

d)

8 steps

28.

How many inputs will a decimal-to-BCD encoder have?

a)

4

b)

6

c)

10

d)

12

29.

Decoder is a

a)

combinational circuit

b)

sequential circuit

c)

complex circuit

d)

gate

30.

7. The number of min terms for an expression comprising of 3 variables?

a)

a) 8

b)

b) 3

c)

c) 0

d)

d) 1

31.

8. The logical sum of two or more logical product terms is called __________

a)

a) SOP

b)

b) POS

c)

c) OR operation

d)

d) NAND operation

32.

9. The expression Y=(A+B)(B+C)(C+A) shows the _________ operation.

a)

a) AND

b)

b) POS

c)

c) SOP

d)

d) NAND

33.

which of the following circuits can be used as parallel to serial converter?

a)

Multiplexer

b)

Demultiplexer

c)

Digital counter

d)

Decoder

34.

The number of inputs and outputs in a full adder are

a)

2 and 1

b)

2 and 2

c)

3 and 2

d)

3 and 3

35.

which device has one input and many outputs

a)

flip flop

b)

multiplexer

c)

demultiplexer

d)

counter

36.

Break the line, change the sign.

a)

Associative Property

b)

Distributive Property

c)

Commutative Property

d)

DeMorgan's Theorem

37.

The rightmost bit of a binary number. This bit has the number's smallest positional multiplier.

a)

Most Significant Bit

b)

Minterm

c)

Maxterm

d)

Least Significant Bit

38.

The leftmost bit in a binary number. This bit has the number's largest positional multiplier.

a)

Most Significant Bit

b)

Minterm

c)

Maxterm

d)

Least Significant Bit

39.

Algebraic process used as a tool in the design and analysis of digital systems. Only two values are possible, 0 and 1.

a)

Boolean Algebra

b)

Boolean Expression

c)

Boolean Theorems

d)

Boolean Variable

40.

Rules that can be applied to Boolean algebra to simplify logic expressions.

a)

Boolean Algebra

b)

Boolean Expression

c)

Boolean Theorems

d)

Boolean Variable

41.

Find the decimal addition 6+8 in bcd

a)

0001 0100

b)

0110 1000

c)

1010

d)

1000 0110

42.

Find the excess-3 code for the decimal numbers 592

a)

0101 1001 0010

b)

1000 1100 0101

c)

0101 1001 0011

d)

1100 1111 1110

43.

A function F(A, B, C) defined by three Boolean variables A, B and C when expressed as sum of products is given by

F=A'B'C'+A'BC'+AB'C'

The product of sums (POS) form of the function F is (GATE 2018)

a)

(A+B+C)(A+B'+C)(A'+B+C)(A+B'+C')

b)

(A+B+C')(A+B'+C')(A'+B'+C)+(A'+B'+C')

44.

The output of the combinational circuit given is (GATE 2016)

a)

A+B+C

b)

A(B+C)

c)

B(C+A)

d)

C(A+B)

45.

In the figure shown, the output ܻ is required to be ܻ Y=AB+ C'D'.The gates G1 and G2 must be, respectively, (GATE 2015)

a)

NOR,OR

b)

OR,NAND

c)

NAND,OR

d)

AND,NAND

46.

Simplify the Boolean function F = $\Sigma$ (1,2,4,7)

a)

F = x'y'+yz+xz

b)

F = x'y'z+ x'yz'+xy'z'+xyz

c)

F = z+xy+yz

d)

F = xyz+x'y'z'

47.

Reduce the following function using K-Map.
F = $\Sigma\ \left(0,1,3,7\right)\ +\Sigma d\ \left(2,5\right)$

a)

F = A' + C

b)

F = A + C

c)

F = A'+C'

d)

F= A'B'+A'C+BC

48.

Simplify the function F = $\Sigma$ (0,1,3,4)

a)

F = AC+BC

b)

F = AB+AC

c)

F= B'C'+A'C

d)

F=A'C'+B'C'

49.

Using the Karnaugh Map, find the logical expression.

a)

A'B'

b)

AB'

c)

A'B

d)

AB

50.

What is the simplified expression?

a)

B' + D

b)

B'D

c)

B + D'

d)

AB + CD

51.

What is the Logic Expression (equation) for this truth table?

a)

(A'+B)(A+B')(A+B)

b)

A'B + AB' + AB

c)

(A'B)(AB')(AB)

d)

A + B

52.

What is the simplified expression?

a)

B'

b)

AB

c)

A'B'+AB'

d)

AC+AB

53.

What is the simplified expression?

a)

AB

b)

A'B+AB

c)

B

d)

AC+AB

54.

1. Simplify f(A,B,C,D)=∑m(2,3,6,7,10,11,14,15)

a)

A

b)

B

c)

C

d)

D

55.

1. Simplify f(A,B,C,D)=∑m(3,7,11,15)

a)

CD

b)

C'D

c)

CD'

d)

C'D'

COMBINATIONAL DIGITAL CIRCUITS

Total questions: 55

Worksheet time: 34mins

Similar Resources on Wayground