B.Sc-B.Sc Electronics 1st Sem EL1 - T2 : Principles of Digital Electronics(University of Pune, Pune-2013)
F.Y. B.Sc.
SEAT No. :
[Total No. of Pages : 2
ELECTRONIC SCIENCE
EL1 - T2 : Principles of Digital Electronics
(2008 Pattern) (Paper - II)
Time : 3 Hours] [Max. Marks : 80
Instructions to the candidates:
1) All questions are compulsory.
2) Neat labelled diagrams must be drawn wherever necessary.
3) Use calculator and log table is allowed.
4) Figures to the right indicate full marks.
Q1) Answer the following questions in brief :
a) What is the radix used in the case of binary and hexadecimal?
b) Why NAND and NOR gates are called as universal gate?
c) Draw logic diagram for logic equation Y = (A + B).C
d) Subtract (1001) from (1100) using the 1’s complement method.
e) Define :
i) Combinational logic circuit. ii) Sequential logic circuit.
f) Draw logic diagram and write truth table for T - flip - flop. g) Define the terms noise immunity and noise margin.
h) State the basic principle of operation of static RAM cell and Dynamic
RAM cell.
Q2) Answer any four of the following : [16]
a) Convert the following.
i) (101110)2 = (......)Gray
ii) (0110)Gray = (........)2
b) Draw logic diagram of two input OR gate using diode. Explain its action.
c) Simplify following expression using K - Map.
Y = ABCD + ABCD + ABCD + ABCD
d) With the neat diagram explain working of parallel 4 - bit binary subtractor.
e) Draw neat diagram of key - board encoder. Explain its operation with
truth table.
f) Explain working of clocked R - S flip - flop with logic diagram and truth
table.
P.T.O.
Q3) Answer any four of the following : [16]
a) Convert the following expression into their standard SoP forms.
i) Y = AB + AC + BC
ii) Y = A + B + C + ABC
b) Draw full adder circuit using half adders. Write the logic expression for
sum and carry out. Explain with truth table. c) Write a note on priority encoder.
d) Draw the circuit, truth table and waveforms of 4 - bit binary counter.
e) Draw the circuit of CMOS NAND gate, explain its action.
f) Describe the classification of memory based on technology, function &
uses.
Q4) Answer any four of the following : [16]
a) State and prove De Morgan’s theorem.
b) What do you mean by seven - segment display? Which are the different
types of seven segment display?
c) State the modes of operation of shift registers with block diagram.
d) Explain the action of NOR gate using RTL logic.
e) List the performance characteristics of digital integrated circuits. Explain
power dissipation.
f) Explain the structural organization of memory chip.
Q5) Answer any four of the following : [16]
a) i) What is a gray code?
ii) Draw AND gate circuit with transistor, write truth table for it.
b) i) What is the function of strobe?
ii) Draw the circuit to obtain 4 to 1 multiplexer using 2 to 1 multiplexer.
c) i) State the different applications of shift register.
ii) What is clock? What are various method of triggering a flip -flop?
d) i) What is synchronous counter? Find out total propagation delay of
4 - bit synchronous counter, if propagation delay of a flip - flop is 20 nsec.
ii) List the function of following IC’s IC 7495 and IC 7490.
e) i) What is meant by open collector gates? State its advantages.
ii) Describe the term saturated and non - saturated logic families.
f) i) State the different types of logic families.
ii) State the prominent manufacturers of integrated circuit
| Earning: Approval pending. |
