# QUESTION PAPER 4 May/June 2015

IMU campuses and affiliated colleges previous year question papers for semester exam.

Nautical Electronics Paper – IV (T 2405)
Date : 15.06.2015 Maximum Marks: 70
Time: 3 Hrs Pass Marks : 28
Note: Attempt any FIVE questions. All questions carry equal marks. (5 x 14 Marks = 70 Marks)
1. (a) What are logic gates? Show the logic symbols, truth tables and Boolean equations for OR, AND and NOR gates.
(b) Develop the circuit of half adder. What are its limitations? How will you develop the circuit of full adder and explain.
2. (a) Draw a detailed block diagram of Timer 555.Explain the function of each block.
(b) Explain the circuit of timer 555 as astable multi vibrator. Show necessary wave forms
3. (a) What are flip flop circuits? Where they are primarily be used. Explain the working of basic flip flop using transistors.
(b) Draw AND-OR logic circuit for Y = ABC + AB̄C + ABC̄. Simplify the equation as much as possible using Boolean theorem.
4. Define microprocessor. Draw a detailed block diagram of 8085 microprocessor and explain the function of ALU, Interrupt control, Instruction register, status flag, program counter, stack pointer and Accumulator.
5 . (a) State and explain De-Morgan’s theorem 1 and 2. Show the necessary logic circuit to prove the theorem. A truth table has output 1 for each of these inputs. ABCD = 0011, ABCD = 0101, ABCD = 1000 and ABCD = 1101. What are the fundamental products for these inputs.
(b) Prove the Boolean relation.
(i) AB̄ + ĀB = ( A+B ) ( Ā+B̄)
(ii) A+ĀB = A + B
6. (a) Define multiplexer circuit. Where they are used. Show the circuit of 8-to-1 line multiplexer. With the example and truth table.
(b) Write a complete program in assembly language to add three numbers such as 10H, 15H and 20H.
Store these number in register A, register B and register C. Store the result of addition in the memory location 8500.
7. Write short notes on any TWO of the following:
(a) NAND logic gate as Universal gate.
(b) Types of semiconductor memories.
(c) Binary ripple counter.
******