# Digital Electronics Mcqs

This set of Electrical engineering Multiple Choice Questions & Answers (MCQs) focuses on study of “ Digital Electronics ”. These questions are chosen from a collection of most authoritative and best reference books on Electrical engineering. Our aim is to prepare an individual for competitive exams like NTS, GAT, ECAT, University and College entrance exams, Jobs and interviews. One should practice our MCQS to assimilate Digital Electronics comprehensively.

## 2. A NAND gate is called a universal logic element because______________?

It is used by everybody

Any logic function can be realized by NAND gates alone

All the minization techniques are applicable for optimum NAND gate realization

Many digital computers use NAND gates

## Answer & Solution

**B . Any logic function can be realized by NAND gates alone**

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## 3. In which of the following base systems is 123 not a valid number ?

Base 10

Base 16

Base8

Base 3

## 4. The binary code of (21.125)10 is_______________?

10101.001

10100.001

10101.010

10100.111

## Answer & Solution

**A . 10101.001**

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## 5. Digital computers are more widely used as compared to analog computers, because they are______________?

Less expensive

Always more accurate and faster

Useful over wider ranges of problem types

Easier to maintain

## Answer & Solution

**C . Useful over wider ranges of problem types**

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## 6. Consider the representation of six-bit numbers by two’s complement, one’s complement, or by sign and magnitude: In which representation is there overflow from the addition of the integers 011000 and 011000 ?

Two’s complement only

Sign and magnitude and one’s complement only

Two’s complement and one’s complement only

All three representations

## Answer & Solution

**D . All three representations**

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## 7. (1(10101)2 is_______________?

(37)10

( 69)10

(41 )10

## 8. What is the octal equivalent of the binary number : 10111101 ?

675

275

572

573

## 9. The number 1000 would appear just immediately after__________________?

FFFF (hex)

1111 (binary)

7777 (octal)

All of the above

## Answer & Solution

**A . FFFF (hex)**

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## 10. The number of Boolean functions that can be generated by n variables is equal to_________________?

2n

22 n

2n-1

## 11. Positive logic in a logic circuit is one in which______________?

Logic 0 and 1 are represented by 0 and positive voltage respectively

Logic 0 and, -1 are represented by negative and positive voltages respectively

Logic 0 voltage level is higher than logic 1 voltage level

Logic 0 voltage level is lower than logic 1 voltage level

## Answer & Solution

**D . Logic 0 voltage level is lower than logic 1 voltage level**

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## 12. Among the logic families, the family which can be used at very high frequency greater than 100 MHz in a 4 bit synchronous counter is__________________?

TTLAS

CMOS

ECL

TTLLS

## 13. An OR gate has 6 inputs. The number of input words in its truth table are________________?

6

32

64

128

## 14. NAND gates are preferred over others because these__________________?

Have lower fabrication area

Can be used to make any gate

Consume least electronic power

Provide maximum density in a chip

## Answer & Solution

**B . Can be used to make any gate**

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## 15. An AND gate will function as OR if________________?

All the inputs to the gates are “1”

All the inputs are ‘0’

Either of the inputs is “1”

All the inputs and outputs are complemented

## Answer & Solution

**D . All the inputs and outputs are complemented**

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