24043-DIGITAL ELECTRONICS IMPORTANT QUESTIONS

KUMARAN POLYTECHNIC COLLEGE

DIPLOMA IN ELECTRICAL AND ELECTRONICS ENGINEERING

SUBJECT CODE    : 24043

SEMESTER             : IV SEMESTER
STAFF INCHARGE: N.SURESH KUMAR,N.DILLI BABU

SUBJECT TITLE    : DIGITAL ELECTRONICS

IMPORTANT QUESTIONS

UNIT-I

PART-A

1.      Convert (64)10 in to Hexadecimal.

2.      Why NAND and NOR gates are called universal gates?

3.      Write the truth table of Ex-OR Gate.

4.      Simplify Y=A.B using DeMOrgan’s theorem.

5.      Convert (23)10 in to binary.

6.      Draw the logic diagram of Ex-OR Gate

7.      State De- Morgan’s theorem.

8.      Simplify the expression using Boolean technique Y=(A+B)(A+B)

9.      Construct the logic circuits AB + AB.

10.  Define fan IN and fan OUT.

11.  Simplify the expression by using Boolean techniques AB + AB +AB + AB

12.  Convert (175)8 in to decimal.

13.  Define Tristate gate

14.  Draw the logic diagram for NOR gate.

PART-B

1.      Realize all gates using NAND gate.[8]

2.      Convert (ABC) 10 into octal.[4]

3.      Simplify the following function using ‘K’ map f(A,B,C,D)=∑(4,5,6,7,12,13,14,15). [8]

4.      Explain the working of TTL logic.[4]

5.      Convert (25B)H  to its octal equivalent. [4]

6.      Simplify the following using K-Map Σ (0,1,2,3,11,12,14,15).[4]

7.      Explain TTL logic and its characteristics .[4]

8.      Convert (88)8 in to hexadecimal [4]

9.      State the De-Morgan’s theorem [4]

10.  Simplify the following function using K-maps Σ 0, 2,4,6,8,10,12,14 [8]

11.  Convert the decimal number 75.82 to its equivalent octal, hexadecimal & Binary numbers.  [8]

12.  Constructing the logic diagram for this Boolean expression is ABC + ABC+ABC+ABC+ABC.[4]

13.  Simplify the given logic function by using Karnaugh simulate its output F=Σ(0,1,2,3,4,5,8,9,10,11,12) [8]

14.  Explain don’t care condition [4]

UNIT-II

PART-A

1.      Add 1011 and 1010.

2.      Define demultiplexer.

3.      Subtract 1010 from 1101 using 2’s complement method.

4.      Define even parity.

5.      Find 2’s complement of 1100110.

6.      Draw the logic diagram of half subtractor.

7.      Write the truth table of full adder.

8.      What is the function of multiplexer?

9.      Define arithmetic circuits.

10.  State MUX & DE- MUX.

11.   Draw pattern of seven segment LED display.

12.  Calculate the 1’s complement of 01101110.

13.  Specify the 2’s complement of 11100111 of binary number.

14.  How many address lines are in 1 to 16 de multiplexer

15.  Define Propagation delay.

16.   What is the basic gate of CMOS logic

PART-B

1.      Explain the operation of half adder with logic diagram.[6]

2.      Explain parity checker and parity generation. [6]

3.      What is multiplexer? Explain the operation of 8 to 1 multiplexer .[8]

4.      Write note on signed binary number. [4]    

5.      Explain the operation of full Subtractor. [6]

6.      Explain 3 to 8 decoder [6]

7.      Explain the operation of BCD adder.

8.      Explain the operation of Demultiplexer.

9.      Explain the operation of Half Subtractor [6]

10.  State and explain parity checker and generator [8]

11.  Write short notes on signed binary numbers. [4]

12.   With the logic diagram explain Full Adder. [4]

13.  With the diagram explain TTL NAND gate and its merits & De-merits. [8]

14.  Explain the working operation of multiplexer with logic diagram. [6]

15.  With the diagram explain CMOS basic gates. [6]

UNIT-III

PART-A

1.      What is flip flop?

2.      Write the modes available in shift register.

3.      Define level triggering.

4.      Define term toggling.

5.      Construct a D Flip flop.

6.      What is the difference between synchronous and asynchronous counter?

7.       List the types of shift register.

8.      What is a counter?

9.      What are the modes available in shift register?

10.  State level triggering.

11.  What is Mod-N counter?

12.  Define Ring counter.

13.  Define combinational circuit.

PART-B

1.      Explain JK Flip Flop with a diagram and a truth table. (6)

2.      Explain 4 bit binary ripple up counter with diagram and waveforms.

3.      Explain the operation of SR FF with diagram and truth table. (6)

4.      With diagram explain serial in parallel out shift register. (6)

5.      Explain the operation of 4 bit synchronous counter with neat diagram. [6]

6.      Explain ‘T’ flip flop. [4]

7.      Explain the operation of serial in serial out shift register with neat diagram. [8] 

8.      Explain the operation of mod-5 counter. (4)

9.      Explain Asynchronous counter [8]

10.  Explain RS-FF [4]

11.  Explain JK-MSFF [6]

12.  Draw & explain 4-bit shift register PISO [6]

13.  Draw the logic diagram of RS-FF and explain its operation [6]

14.  With the logic diagram explain the operation of down counter [6]

15.  Explain the Johnson Counter [8]

16.  Explain parallel IN parallel OUT shift registers [4]

UNIT-IV

PART-A

1.      What is meant by read operation in memory?

2.      Expand EPROM.

3.      Define dynamic memory.

4.      What is non-volatile memory?

5.      What are the types of memory?

6.      Expand EEPROM.

7.      Expand DDR RAM.

8.      Define flash memory.

9.      Differentiate ROM & PROM

10.  How many 8K memory is needed for creating 16K memory?

11.  What is volatile memory

12.   What important component is used for fabricating bipolar RAM Cell.

13.   Define dynamic Ram.

PART-B

1.      Explain ROM organization. [12]

2.      Explain bipolar RAM cell.  [8]

3.      Write the difference between static and dynamic RAM.  [4]

4.      Explain ROM organization [6]

5.      Explain the Read/write operation of static RAM [6]

6.      Explain EPROM in detail. [6]

7.      Write short notes on: (i) SD RAM (ii) Anti-fuse technology.(6)

8.      Explain anti fuse technology [4]

9.      Explain the working operation of Read/write operation [8]

10.  Explain flash memory [4]

UNIT-V

PART-A

1.      What is ALU?

2.      What is program counter?

3.      What is the use of stack pointer register?

4.      List the interrupts available in 8085.

5.      What is a machine cycle?

6.      What is the function of PUSH rp instruction?

7.      State PSW register.

8.      What is the function of accumulator?

9.      Define microprocessor.

10.  What is a POP instruction?

11.  Define Interrupt

12.  write any four addressing modes

13.  write control & status signals 

PART-B

1.      Write notes on evolution of microprocessors. (6)

2.      What are the different addressing modes in 8085? Explain any two of them with examples. (6)

3.      Compare memory mapped I/O and I/O mapped I/O. (6)

4.      Write notes on interrupts in 8085? (6)

5.      Explain the architecture of 8085 with neat diagram. [12]

6.      Draw the Timing diagram of MOV r1,r2  instruction. (12)

7.      Draw and explain timing diagram for LDA address instruction. [12]

8.      Classification of instruction set based on their function with example. [6]

9.      Explain Interrupt and it’s various types. [6]

10.  Difference between memory mapped I/O and I/O mapped I/O. [4]