Download PTU B.Tech 2021 Jan Software Engineering 3rd Sem 78674 Digital Electronics Question Paper

Download PTU (Punjab Technical University) B.Tech (Bachelor of Technology) / BE (Bachelor of Engineering) 2021 January Software Engineering 3rd Sem 78674 Digital Electronics Previous Question Paper

Roll No.
Total No. of Pages : 02
Total No. of Questions : 18
B.Tech. (Software Engineering) (Sem.?3)
DIGITAL ELECTRONICS
Subject Code : BTES-301-18
M.Code : 78674
Time : 3 Hrs. Max. Marks : 60
INST RUCT IONS T O CANDIDAT ES :
1 .
SECT ION-A is COMPULSORY cons is ting of TEN questions carrying TWO marks
each.
2 .
SECT ION-B c ontains F IVE questions c arrying FIVE marks eac h and s tud ents
have to atte mpt any FOUR q ues tions.
3 .
SECT ION-C contains THREE questions carrying T EN marks e ach and s tudents
have to atte mpt any T WO questio ns.
SECTION-A
Write briefly :
1)
Draw the logic symbol and truth table of XNOR gate.
2)
Write down the significance of excess-3 code.
3)
What do you mean by ASCII? Explain.
4)
Compare Boolean algebra and ordinary algebra.
5)
Draw the logic symbol and truth table of D Flip Flop.
6)
Differentiate between edge and level triggering.
7)
Differentiate between synchronous and asynchronous counters.
8)
What do you mean by resolution and accuracy of D/A converters? Explain.
9)
Compare RAM and ROM.
10) Discuss the significance of sample and hold circuit.
SECTION-B
11) Convert 357.24 octal number to decimal number, hexadecimal and binary.
12) Two 4 bit BCD numbers A0 A1 A2 A3 and B0 B1 B2 B3 are required to be added,
resulting in a BCD number. What modifications/alterations are required to be made in the
circuit of 4-bit binary adder? Discuss. Mention clearly the assumptions made, if any.
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13) For a 5-bit resistive divider, determine the following :
a) The weight assigned to the LSB;
b) The weight assigned to the second and third LSB;
c) The change in output voltage due to a change in the LSB, the second LSB, and the
third LSB;
d) The output voltage for a digital input of 10101. Assume 0 = 0 V and 1 = + 10 V.
14) To issue an insurance policy an applicant must fulfil the following requirements. The
applicant must be :
? A married female 25 years old or over, or
? A female under 25, or
? A married male under 25 who has not been involved in a car accident, or
? A married male who has been involved in a car accident, or
? A married male 25 years or over who has not been involved in a car accident.
Find the logical expression which assumes a value 1 whenever the policy is issued.
Realize the circuit using the minimum number of gates.
15) Draw the K-map of the following expression and obtain the minimal SOP form. The
expression is ABCD AC CD ABC ABC .
SECTION-C
16) Draw the logical circuit diagram and explain the working of successive approximation
and dual slope analog to digital convertors.
17) Design a MOD-9 synchronous counter using T and JK flip flops.
18) Explain :
i) Shift registers
ii) NAND and NOR as universal gates
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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