# Interview Questions on Digital Electronics

#### Bybarby

Jul 7, 2020

Hey Guys! If you are looking for a job in the Digital Electronics field, then it’s time to get prepared for the interview with the basic questions and answers. In this field, you can work on mobile phones, sound systems, and many other electronic devices. Your knowledge in this subject can be applied to a wide area of applications such as industrial electronics, micro embedded systems, and military equipment, etc. So to make it easier for you we have come up with a set of important questions and answers. All you need to do is just go through them and make a fast beginning to a promising career.

### Interview Questions on Digital Electronics:

1) What is the difference between Analog and Digital circuits?

ans. Analog circuits operate with continuously varying signals, and these signals are commonly referred to as analog signals.

Digital circuits operate on signals whose values exist at two levels only or have only two values i.e. 0’s (zeros) and 1’s (ones) and these signals are commonly referred to as digital signals, at any given instant of time the value of a digital signal can be either high (1) or low(0).

2) What is the advantage of digital circuits over analog circuits?

ans. Analog circuits are difficult to design since most of the designing processes involved are manual. In addition to these automation techniques for designing these analog circuits fail to do the job efficiently.

Digital circuits are easy to design since automation techniques can be applied at various levels of circuit design. This involves minimum human interaction. Also, they are cheaper than analog circuits.

3) What is the difference between Flip-flops and Latches?

ans. Latches are level triggered which means the output of the latch changes as we change the input. The output of the latch will track the input when the signal is high i.e. when the clock is high 1, the output change if input changes.

Flip-flops are edge-triggered which means the control signal changes its state only when it goes from low to high or high to low. In flip-flop, input will be stored only when there is a rising or falling edge of the clock.

4) Which is faster: Latches or Flip-flops and why?

ans. Latches need fewer logic gates than flip-flop to implement, so latches are faster than a flip-flop.

5) How many types of Numbers System are there?

ans.1.Decimal Number System.
2. Binary Number System.
3. Octal Number System.

6) What is a logic gate?

ans. Logic gates are the basic building blocks of any digital system. It is an electronic circuit having one or more than one inputs and only one output.

7) What are the basic logic gates?

ans. 1.AND gate.
2. OR gate.
3. NOT gate.

NOTE: ( In case you are planning to tell NAND and NOR gates also so just mention that these two are the universal gates or else the interviewer would consider your answer as the wrong one since he asked you only the basic logic gates.)

8) What are the fundamental properties of Boolean algebra?

ans. 1. Commutative Property.
2. Associative Property.
3. Distributive Property.

9) What is Boolean algebra?

ans. Boolean Algebra is used to analyze and simplify the logic circuits. It uses only the binary numbers i.e. 0 and 1 and is also called Binary Algebra or logical Algebra.

10) What are the forms of Boolean expression?

ans. 1. Sum of products (SOP) form
2. Product of sum (POS) form.

### Questions on K-map:

11) What is meant by K-map?

ans. K-map stands for the Karnaugh map. It is a pictorial representation of a truth table and a method to minimize Boolean functions in an easy way.

12) What are Min-term and Max-term?

ans. A Min-term is called Product of sum (POS) because they are the logical AND of the set of variables. It is a Boolean expression which results in 1 for the output of a single cell, and 0s for all other cells in a K-map. If a Min-term has a single 1 and the remaining cells as 0s, it would appear to cover a minimum area of 1s.

A Max-term is called the sum of product (SOP) because they are the logical OR of the set of variables. It is a Boolean expression resulting in a 0 for the output of a single cell expression, and 1s for all other cells in the K-map. If a Max-term has a single 0 and the remaining cells as 1s, it would appear to cover a maximum area of 1s.

13) Define Pair, Quad, and Octet in K-map.

ans. Pair: Two adjacent cells of K-map is called Pair. It cancels one variable in a K-Map simplification.

Quad: A group of four 1s that are horizontal or vertical or form a square is called Quad. It cancels 2 variables in a K-Map simplification.

Octet: An Octet is a group of eight 1s that are adjacent to each other is called an octet. It cancels 4 variables in a K-Map simplification.

14) What is SOP?

ans. When two or multiple product terms are added by a Boolean addition, the output expression is an SOP (Sum of Products).
Eg. A’BC’+ A’BD’ + A’BC’D shows an SOP expression. It can also have a single variable term within the expression like A+ BC + A’B.

15) What is POS?

ans. POS (Product of Sums) is the representation of the Boolean function in which the variables are first summed, and then the Boolean product is applied in the sum terms.
Eg. (A’+B).(A+B’+C) shows a POS expression.

So people! I hope you found this blog useful but it’s not over yet. In the next blog, you would get to learn a few more questions related to combinational and sequential circuits till then stay tuned!