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QUESTION PAPERS
DIGITAL ELECTRONICS
(B.Tech. 3rd Semester,501)
Note:- This paper consist of three Sections Section A is compulsory. Do
any Four questions from Section B and any two questions from Section C.
Section-A Marks:20
1.(a) Application of ASCII ,Excess-3 and gray codes.
(b) Differentiate between combinational and sequential
circuits.
(c) the advantages of edge triggered flip-flops
(d) How subtraction of 4-bit no. is performed by addition?
(e) If two inputs are to be used for a 4 input NAND gate,
discuss the options available with the unused inputs.
(f) A/D accuracy and resolution
(g) Fan in, Fan out, propagation delay terms related to logic
gates.
(h) Special features of content addressable memories.
(i) Advantages and disadvantages of synchronous over
asynchronous counters.
(j) Conversion of 100.55(10) into binary, octal codes.
Section-B Marks : 5 Each
2. Draw the circuit of a 3 to 8 decoder and explain its
operation. How this can be used as a DEMUX.
3. Find the complement of the Boolean function and reduce it to
a minimum number of literals :
B'D+A'BC'+ACD+A'BC.
4. Draw the circuit of a negative edge triggered J-K flip flop
with d.c. pre-set and d.c. clear options using S-R flip flops
and explain its truth table.
5. Draw and discuss the circuit of a dual scope A/D converter.
6. Draw the circuit of a 3- input TTL totem pole NAND gate and explain
its operation.
Section-C MArks:10 Each
7.(a) Mention the various A/D convertors. Discus the comparison
of advantages and disadvantages of each of these.
(b) Simple using Q-M method:
X(A,B,C,D)= SIGMA(0,1,2,8,10,11,14,15).
8.(a) Draw the circuit of Ecl gate and explin its operation.
(b) Discuss the comparison of the important characteristics of
the various IC logic families.
9.(a) Draw the circuit of a BJT RAM cell and explain its
operation
(b) Draw the circuit of a 4-bit shift register and explain its
operation.