Table of Contents

Toggle**Important RGPV Question**

**EX-403 (Digital Electronics Logic Design)**

**IV Sem, EX**

**UNIT-1 Number Systems & Codes**

**Q.1** Design 3-bit data even parity generator and checker.

**(RGPV Nov 2023)Β **

**Q.2** Β Simplify following Boolean expressions:

(i) F(A,B,C,D) = Ξ Ξ(0,1,2,3,4,5,6,7,9,11) Using K-map.

**(RGPV Nov 2023)Β **

**Q.3** Minimize the following functions by Tabular method-

F(A,B,C,D) = Ξ£ m(1,3,7,11,15) + Ξ£d (0,2,5)

**(RGPV Nov 2023)Β **

**Q.4** Give the general procedure with example for converting a multilevel AND-OR diagram into an all NAND diagram.

**(RGPV Nov 2023)Β **

**Q.5** Convert the following codes.

i) (785.B2)16Β = (Β Β Β )10

ii) (1011011.1101)1Β = (Β Β Β Β Β )8

iii) (110101.101101)2 = (Β Β Β Β Β )Gray

iv) (751.231)8Β = (Β Β Β Β )16

**(RGPV June 2023)Β **

**Q.6** Use the tabulation procedure to generate the set of prime implicates and to obtain all minimal expression for

F1Β = (w,x,y,z) = Ξ£(1,5,6,12,13,14) + Ξ£Ξ¦(10,4)

**(RGPV June 2023)Β **

**Q.7** Find the minimal SOP expression for the function f(x, y, z) = Ξ£m (0, 2, 3, 5, 6, 7)

**(RGPV June 2023)Β **

**Q.8** What do you understand by Subtractor? Explain the working principle of half subtractor using suitable diagram and truth table.

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**Q.9** Realize the Boolean expression Z = ABC + AD + CD’ using NAND gates only.

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**Q.10** Explain in detail about Parity generator and checkers.

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**Q.11** Why NAND and NOR gates are called universal gates? Realize AND, OR with the help of NAND and NOR gates.

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**Q.12** Convert the following Β (i) (1001.0101)2Β to Decimal (ii) (137.21)8Β to decimal.

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**Q.13** What is De-Morgan’s theorem? Simplify the given expression using De-Morgan’s theorem.

**(RGPV Dec 2020)Β **

**Q.14** What are Exclusive-OR and Exclusive-NOR gates? Explain with truth table and diagram?

**(RGPV Dec 2020)Β **

**Q.15 **Convert the following:

i) (312.4)4Β to decimal

ii) Binary code 10110 to Hexa code

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**Q.16** Design EX-OR gate with the help of NAND gates only.

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**Q.17** Minimize the following function using K-map and realize using logic gates:

F (A, B, C, D) = Ξ£m (1, 5, 7, 13, 15) + d (0, 6, 12, 14)

**(RGPV June 2020)Β **

**Q.18 **State and prove De-Morgan’s theorem. Also prove the following rules of Boolean algebra:

i) A + A’B = A + B

ii) (A+B) (A+C) = A + BC

**(RGPV June 2020)Β **

**Q.19** Do the following conversions:

i) (101110.0101)2Β β (Β Β Β Β )8

ii) (432A)16Β β ( Β Β Β Β )Β 2

iii) (428.10)10Β β (Β Β )Β 2

**(RGPV June 2020)Β **

**Q.20** Using K-map convert the following standard POS expression into a minimum POS expression, standard SOP expression and minimum SOP expression.

(A’+B+C+D) (A+B’+C+D) (A+B+C+D’) (A+B+C’+D’) (A’+B+C+D’) (A+B+C’+D).

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**Q.21** Write a short notes on Parity Generator

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**Q.22** Write short notes on Β Parity generators and checkers

**(RGPV Dec 2020)**

**UNIT β 2 Combinational Circuits**

**Q.1** Design Full-Adder using 2-half adder and an OR gate.

**(RGPV Nov 2023)Β **

**Q.2** Design 4 input priority encoder using combinational gates.

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**Q.3** For the Function F(A,B,C,D) = Β Ξ£m (0,1,3,4,7,8,9,11, 14, 15), define multiplexers implement using

1) 4Γ1 MUX

ii) 2Γ1 MUX

**(RGPV Nov 2023)Β **

**Q.4** Define decoder. Construct 3×8 decoder using logic gates.

**(RGPV June 2023)**

** Q.5 **Write a short notes on:

i) BCD Adder

ii) Priority Encoder

iii) Decoding in Counter

**(RGPV June 2023)Β **

**Q.6** What is De-Multiplexer? Design the given expression using 4Γ1 multiplexer F(A,B) = Δ + B

**(RGPV June 2022)Β **

**Q.7** What is half adder? Write its truth table and design the logic circuit.

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**Q.8** Define Encoder and design 2-bit magnitude comparator.

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**Q.9 **What is full substractor? Write its truth table and design the logic circuit.

**(RGPV Dec 2020)Β **

**Q.10** What is Multiplexer? Design the given expression using 4Γ1 multiplexer. F (A, B) = AB+AB

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**Q.11** How will you implement full-adder using half-adder? Explain the circuit diagram.

**(RGPV June 2020)Β **

**Q.12** Implement the following expression using 8 to 1 multiplexer:

F (A, B, C, D) = Ξ£m (0, 3, 4, 7, 8, 9, 13, 14)

**(RGPV June 2020)Β **

**Q.13** Draw and explain the look ahead carry generator.

**(RGPV June 2020)Β **

**Q.14** Write short notes on BCD Adder

**(RGPV Dec 2020)**

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**UNIT β 3 Sequential Logic CircuitΒ **

**Q.1** Draw the clocked Master-Slave J-K flip-flop configuration and explain how it removes race-around condition in J-K flip-flops?

**(RGPV Nov 2023)Β **

**Q.2** Differentiate between Latch and Flip-Flop. Analyzing the synchronous sequential circuit, where input and output equation are- JA = x, JBΒ = x, KAΒ = Bβ, KBΒ = A find- Logic diagram, state table, state equation, state diagram.

**(RGPV Nov 2023)Β **

**Q.3** Convert the SR F-F to JK F-F .

**(RGPV Nov 2023)Β **

**Q.4** Draw a neat circuit diagram of a negative edge triggered JK flip-flop and explain its operation.

**(RGPV June 2023)Β **

**Q.5** Prepare the state table and excitation table for the Sequential machine shown below. Use T flip flop.

**(RGPV June 2023)**

**Q.6** Draw a neat circuit diagram of positive edge triggered D flip-flop and explain its operation.

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**Q.7** What do you mean by flip-flop? Explain with the help of diagrams and tables?

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**Q.8** What are Latches? Write applications of flip-flop.

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**Q.9** Convert SR flip-flop to JK flip-flop.

**(RGPV June 2022)Β **

**Q.10** What do you mean by Master-Slave Flip-Flop? Explain with the help of diagrams and tables.

**(RGPV Dec 2020)**

** Q.11**Β Distinguish between Latch and Flip-Flop.

**(RGPV Dec 2020)Β **

**Q.12** Explain J-K flip-flop and D-flip-flop.

**(RGPV Dec 2020)Β **

**Q.13** What is race around condition? Explain with the help of timing diagram. How is it removed in basic flip-flop circuit?Β

**(RGPV June 2020)Β **

**Q.14** Design sequence generator using J-K Flip-Flop for the following sequence:

1β3β5β6β7β1.

**(RGPV June 2020)**

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**UNIT β 4 Registers & Counters**Β

**Q.1** Design a synchronous counter using JK flip-flop for the following input sequences: 0-1-2-4-5-6-0Β

**(RGPV Nov 2023)Β **

**Q.2** With the help of diagram, explain the operation of universal shift register.

**(RGPV Nov 2023)Β **

**Q.3** Explain Moore type of synchronous sequential machine (FSM) using block diagram and suitable example.

**(RGPV Nov 2023)**

**Β Q.4** Draw and explain the working of Johnson Counter.

**(RGPV June 2023)Β **

**Q.5** Draw a 4-bit Asynchronous UP counter and discuss its characteristics. Draw the waveforms.

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**Q.6 **What are the different types of registers? Explain the Parallel Input Serial Output shift register.

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**Q.7** What is Asynchronous and Synchronous counter? Give some applications of counter.

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**Q.8** Write about Ring counter and universal shift registers.

**(RGPV June 2022)Β **

**Q.9** Explain BCD counter with the help of diagram.

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**Q.10** What is UP and DOWN counter? Give some applications of counter?

**(RGPV Dec 2020)Β **

**Q.11** Write about Johnson counter and universal shift registers.

**(RGPV Dec 2020)**

**Q.12**Β Explain different types of registers.

**(RGPV Dec 2020)Β **

**Q.13** Explain the difference between asynchronous and synchronous counter. How lockout condition in counter is avoided?

**(RGPV June 2020)Β **

**Q.14** Explain with neat diagram working of serial- in serial-out 4-bit shift register. Draw necessary timing diagram.

b) Draw and explain:

i) Johnson Counter

ii) BCD Counter

**(RGPV June 2020)**

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**UNIT β 5 RAM & ROM**Β

**Q.1** Realize the full adder circuit using the PAL.

**(RGPV Nov 2023)Β **

**Q.2** Draw the basic circuit of a ROM cell and explain its working.

**(RGPV Nov 2023)Β **

**Q.3** With a neat diagram explain the operation of R-2R DAC.

**(RGPV Nov 2023)Β **

**Q.4** What are sequential programmable devices? Draw the sequential programmable logic for a basic microcell logic.

**(RGPV June 2023)Β **

**Q.5** Explain the working of successive approximation ADC. Mention the advantages and disadvantages.

**(RGPV June 2023)Β **

**Q.6** What is ROM and its types?

**(RGPV June 2022)Β **

**Q.7** Explain about combinational PLD’s.

**(RGPV June 2022)Β **

**Q.8** Write short notes on the following:-

a) RAM

b) PLA and PAL

**(RGPV June 2022)Β **

**Q.9** Explain about PLA and PAL and give difference between them.

**(RGPV Dec 2020)Β **

**Q.10** What is RAM?

**(RGPV Dec 2020)Β **

**Q.11** Write short notes on Digital to Analog converters

**(RGPV Dec 2020)Β **

**Q.12** Draw the basic structure of CPLD. Explain its features in brief.

**(RGPV June 2020)Β **

**Q.13** Explain analog to digital conversion using successive approximation.

**(RGPV June 2020)Β **

**Q.14** Write short notes on (any two):

a) PAL

b) Master-slave FF

c) ROM

**(RGPV June 2020)**

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**— Best of Luck for Exam —**