Important Short Questions Answers: Boolean Algebra and Logic Gates

1. Define binary logic?

Binary logic consists of binary variables and logical operations. The variables are designated by the alphabets such as A, B, C, x, y, z, etc., with each variable having only two distinct values: 1 and 0. There are three basic logic operations: AND, OR, and NOT.

2. What are the basic digital logic gates?

The three basic logic gates are, AND gate OR gate NOT gate.

3. What is a Logic gate?

Logic gates are the basic elements that make up a digital system. The electronic gate is a circuit that is able to operate on a number of binary inputs in order to perform a particular logical function.

4. Which gates are called as the universal gates? What are its advantages?

The NAND and NOR gates are called as the universal gates. These gates are used to perform any type of logic application.

5. Mention the important characteristics of digital IC’s?

Fan out-Power dissipation Propagation Delay Noise Margin Fan In-Operating temperature Power supply requirements.

6. Define Fan-out?

Fan out specifies the number of standard loads that the output of the gate can drive without impairment of its normal operation.

7. Define power dissipation?

Power dissipation is measure of power consumed by the gate when fully driven by all its inputs.

8. What is propagation delay?

Propagation delay is the average transition delay time for the signal to propagate from input to output when the signals change in value. It is expressed in ns.

9. Define noise margin?

It is the maximum noise voltage added to an input signal of a digital circuit that does not cause an undesirable change in the circuit output. It is expressed in volts.

10. Define fan in?

Fan in is the number of inputs connected to the gate without any degradation in the voltage level.

11. State duality principle

“Every algebraic expression deducible from the postulates of Boolean algebrad ifremainsthe v operators and identity elements are interchanged.

12. Write the applications of gray code.

Used in telegraphy, for robust communication and in error detection and correction..

13. What are the limitations of Karnaugh map?

The size can be limited to 6 variables and also can be used for simplifying Boolean expressions.

14. What are error detecting codes?

To maintain the data integrity between the transmitter and receiver, extra bit or more than one bit are added in the data. The codes which allow only error detection are called error detecting codes.

15.            What are different ways to represent a negative number?

ü Ordinary arithmetic-minus sign

ü Signed magnitude-MSB bit as 1.

ü 1’s complement

Question 

1.                 (i) Minimize the following_=̅expression_̅+̅ using_̅+ k-map_{̅ + ̅ ̅ + ̅} (ii)State and prove the De-morgan’s theorem.

2.                 Simplify the following Boolean function by using Tabulation method F (w, x, y, z) =_ (0, 1, 2, 8, 10, 11, 14,15)

3.                 Simplify the following Boolean functions by using K-Map in SOP & POS. F (w, x, y, z) =_ (1, 3, 4, 6, 9, 11, 12, 14)

4.                 Simplify the following Boolean functions by using K-Map in SOP & POS. F (w, x, y, z) =_ (1, 3, 7, 11, 15) + d (0 , 2, 5)

5.      Reduce the given expression  [(AB)‘ + A‘ +AB‘]

6. Reduce the following function using k-map technique f(A,B,C,D)= _ M(0, 3, 4, 7, 8, 10, 12, 14)+d (2, 6)