# Sample Paper for Diploma in Computer Science–Digital Electronics

Sample Paper for Diploma in Computer Science –Digital
Electronics

### Duration -3 Hours                                                                                      Max Marks: 60

Note:  1. Attempt any FIVE questions.

2. All questions carry equal marks.

1.                  What are Demorgan’s theorems? Write them in equation for. Prepare their truth table to prove their correctness.

2.                  What is an exclusive OR gate? Draw its symbol and prepare truth table for 2-input exclusive OR gate.

3.                  Explain the principles of LED. Draw a circuit showing LEDs used in 7 segments display.

4.                  When a multiplexer is used as a logic function generator, where are the inputs connected? Explain in detail.

5.                  What is SR latch? Draw its logic circuit using:

• NOR gates
• NAND gates. Also explain its working

6.                  A digital gate has V cc = 5 V. The input current in 3 mA for low output and 1 maA for high output. Find out power dissipation for 50 % duty cycle.

7.                  What is half adder? Draw its circuit.

8.                  What is 9’s complement? How is it different from 10’s complement? Where are they used?

9.                  What is the most important characteristic of Gray code? Prepare a table showing the 4 bit Gray code. Explain the rule for conversion of Binary number to Gray code.