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amity solved assignment MCA Digital electronics

1

a) Draw the circuit of a 3 to 8 decoder and explain its operation. How this can be used as a DEMUX.

b) Design and explain Priority encoder
   

2

Do as directed

a) Conversion of 100.55 base 10 into binary, octal codes.

b) Conversion of 1111010011011110 base 2 to decimal, hexadecimal.
   

3

Differentiate between:

i) Combinational and Sequential Logic Circuits.  ii) Synchronous and Asynchronous Counters
   

4

a) Explain the working of master-slave JK flip flop. State its merit. What is Race problem in flip- flops?

 

b) Design a negative edge triggered T flip flop. The circuit has two inputs, T(toggle) and C(clock) and output Q and Q’. The output state is complemented if T=1 and the clock C changes from 1 to 0. Otherwise under any other input condition, the output Q remains unchanged.
   

5

a) Prove the Demorgan’s laws using Boolean algebra.

b) Find the minimal sum of product expression for the following Switching function. F (x1, x2, x3, x4, x5) = Sm (1, 2, 3, 6, 8, 9, 14, 17, 24, 25, 26,

   27,  30, 31) + Sd(4,5)

 

 

 Case Study An m: 1 multiplexer has m data inputs; log2m control signals and produces a data output which is equal to the input selected by the control signals. Each different combination of control signals selects a different input. Present an implementation, either as a circuit diagram or as equations, of an 8: 1 multiplexer. Show how 8: 1 multiplexers can be cascaded to build a 64: 1 multiplexer. 

 

1.

A Gray code is a sequence of codes which differ in one bit position at each step. For example 00, 01, 11, 10, 00 …is a two-bit Gray code. Design a counter made from JK flip-flops to produce a three-bit Gray code.

 
 

2.

Mention the various A/D convertors. And Draw and discuss the circuit of a dual scope A/D convertor. Also discuss the comparison of advantages and disadvantages of each of A/D convertor.

 
 

3.

Draw the circuit of a 4-bit shift registers and explains its operation. Also explain Various different types of shift register with circuit diagram.

 
 

 

Question No: 1

Binary 1000 will be the result of which of the following
   

Binary 1000 - 100

Binary 1011 - 1111

Binary 1111 - 111

Binary 11111 – 1111
 
   

Question No: 2

Decimal 14 in binary system can be written as____
   

1111

1110

0111

1100
 
   

Question No: 3

In digital electronics, which of the following voltage levels does not denote logic '0'?
   

0 volt

0.4 volt

<0.8 volt

none of the above
 
   

Question No: 4

Aside from the binary system, what other number system is commonly used in digital systems?
   

decimal

hexadecimal

scale-of-2

none of the above
 
   

Question No: 5

8421 code is
   

Self -complementing code

Weighted code

Non-weighted code

Alphanumeric code
 
   

Question No: 6

ASCII code is a
   

5-bit code

7-bit code

8-bit code

10-bit code
 
   

Question No: 7

In synchronous counters the clock input of each of the bi-stables are connected together so that each changes state at the same time.
   

True

False

None of Above

All of Above
 
   

Question No: 8

Decimal that converts from decimal to binary numbered is called _______________
   

Encoder

Decoder

Converter

CPU
 
   

Question No: 9

The binary number 101100.110 in octal number will be
   

152.6

154.6

145.2

174.5
 
   

Question No: 10

6 64 K is ___
   

6400

64000

65536

64536
 
   

Question No: 11

Which of the following are universal gate: a)
   

AND

NAND

NOR

OR
 
   

Question No: 12

DAC converts _______ 
   

 

  Analog to Digital

 

    Digital to Analog

 

   Both a and b

.
 
   

Question No: 13
 
   

 

 A6.78

 

 A7.78_

 

   78.A7

 

 78.A6
 
   

Question No: 14

An array of flip-flop is also known as  ________
   

 

   Counter

 

    D Flip-Flop

Register

 

 All of the above
 
   

Question No: 15

Which of the following are based on digital systems?
   

 

Electronic calculator

 

  Voting Machine

 

Traffic signal

 

 None of the above
 
   

Question No: 16

An OR gate is ENABLED by connecting one of its inputs to logic level____.
   

0

1

0 or 1  

None of the above
 
   

Question No: 17

How many data inputs contains by a 64 output lines decoder?
   

64

6

2

All of the above
 
   

Question No: 18

A flip-flop with active low preset input will have Q’= _____ when preset is counted to low.
   

1

0

1 or 0

None of the above
 
   

Question No: 19

How many maximum possible number of states in a clocked sequential circuit having 6 Flip-flops?
   

32

64

16

None of the above
 
   

Question No: 20

A dynamic RAM is fabricated using  ______ technology.

 
   

 

CMOS

 

 MOS

CHIP

none
 
   

Question No: 21
 
   

 

    D1

1D_

 

  D2

 

   DE
 
   

Question No: 22

In Boolean algebra the OR function is represented by the '+' sign.
   

True

False

All of the above

None of the above
 
   

Question No: 23

A signal having discrete values is known as
   

a digital signal

an analog signal

a natural signal

none of the above
 
   

Question No: 24

How many nibbles count in the number 1111 1110?
   

4

8

2

16
 
   

Question No: 25

If 2 in binary system 010 then 6 will be
   

011

0111

1110

None of the above Q15
 
   

Question No: 26

What is binary equivalent of FC6 is
   

1111 1100 0110

011011001010

None of the above

Both of the above
 
   

Question No: 27

The 2’s complement of 100001011 is __________
   

011110101

001110100

001111100

000110100
 
   

Question No: 28

Which logic gate has the following truth table?

 
 

Input

Input

Output

A

B

C

 

 

 

0

0

1

 

 

 

0

1

0

1

0

0

 

 

 

1

1

0

 

 

 

 
   

An exclusive NOR gate

A two-input AND gate

A two-input OR gate.

An exclusive OR gate
 
   

Question No: 29

In which gate output is complements of its input:
   

AND

NOT

NOR

None of the above
 
   

Question No: 30

In the Karnaugh map shown below, which of the loops shown represents a legal grouping?

 

 

 

 

\

 

_

-

 

h

\^

 

 

 

00

 

 

1

<i

^~~B

 

 

 

 

 

 

 

 

 

 

 

 

t

 

 

 

\

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

01 CD

 

• __

 

0

 

 

v

¥

^~-c

 

 

 

 

 

 

 

 

 

 

 

 

 

 

o

 

 

 

0

 

 

 

 

 

 

 

 

11

 

 

1

 

 

 

" ^

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

^-D

 

 

10

0

 

 

1

 

l

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
   

A

B

C

D
 
   

Question No: 31

How many gate inputs are required to realize the following expression?

  

F=(B+C+D)(B+C+E)(A+B+C+E)(F+G)
   

14

15

16

All the above
 
   

Question No: 32

How many cells present in a 4-variable format?
   

16

8

32

  All the above
 
   

Question No: 33

Is in positive logic circuits it is normal to use +5V for true and 0V for false?
   

   True

   False

None of the above

All of the above
 
   

Question No: 34

A logic circuit that accepts one data input and distributes it over several outputs is known as  ____ .
   

 

  Decoder

 

  DMUX

 

   Priority Encoder

 

 All of the above
 
   

Question No: 35

 

 

 

 

 

 

 

  

 

 

 

 

 

 

 
   

 

 2-to-4 bit Binary decoder

 

  4-to-2 bit Binary decoder

 

  2-to-4 bit Priority decoder

 

   None of the above
 
   

Question No: 36

A full adder can be made by adding ____ 
   

 

 Two half adder

 

  Two half subtractor

 

  Both a and b

None of the above
 
   

Question No: 37

Master-Slave J-K flip-flop doesn’t solves the race around problem occurs in JK-flip-flop
   

 

True

 

   False

.

.
 
   

Question No: 38

In a ________ , the output of the last flip-flop is connected back to the input of the first flip-flop.
   

 

Johnson counter

 

 Ring counter

 

 D-type flip-flop

 

   None of the above
 
   

Question No: 39

How many flip-flops are needed for an 8-bit counter?
   

 

    Two

 

      Three

 

    Four

 

  Eight
 
   

Question No: 40

Which of the following can be used in Keyboard encoder?
   

 

  Shift registers

 

 Flip-Flop

 

 Registers

 

 All of the above
 
   

 
 
   

 

 

 

students may email their requirements with the link of the assignment and their phone number  at solvezone@gmail.com

 

 

 

 

 

 

 

 

 

University:  AMITY Year:  2015
Subject: 
Digital electronics
Course: 
MCA