# Dr.A.P.J.Abdul Kalam University BE - IT III SEM Digital circuit & Design [IT-222] Dec - 2020 Question Paper

Dr.A.P.J.Abdul Kalam University

Bachelor of Engineering

Third Semester Main Examination, Dec-2020

Digital circuit & Design [IT-222]

Branch - IT

Time: 3:00 Hrs

Max Marks 70

Note :
1. Attempt any five questions out of eight.
2. Answer should be precise & to be point only.

Q.1 (a) What is Boolean algebra explain with suitable example, as well as defined of canonical SOP and
POS form.
(b) Why gray code use in k-map and how come excess 3 is a self-complementing code and convert
excess 3 to BCD code.

Q.2 (a) What is a basic difference between basic gate and universal gate? How many two input NAND
gate are required to perform the action of a two input OR gate and its draw?
(b) What is Adder? Explain of ripple carry and subtractor.

Q.3 (a) What does edge triggered and level triggered mean? And also defined of edge triggered flip-flop.
(b) Explain of Johnson ring counter and synchronous ring counter

Q.4 (a) What is flip-flop? Explain all type of flip-flop with truth tables?
(b) Draw multiplexer and demultiplexer circuit and explain its application.

Q.5 (a) Briefly explain of RTL, DTL, TTL.
(b) What is difference between NMOS, PMOS and CMOS logic?

Q.6 (a) Explain of Schmitt trigger circuit.
(b) Explain of 7 segment LED display.

Q.7 (a) What is DAC?
(b) What is Multivibrator? How does a multivibrator circuit work?

Q.8 Write short notes on:
(i) Draw 8*1 MUX using 2×1 Mux
(ii) Explain shift left/right registers
(iii) Gray to binary code conversion
(iv) Explain encoder

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