### Unit 1 (DE)

# Theory

### Quiz

The OR operation is performed by which property in Boolean algebra?
Associative properties
Commutative properties
Distributive properties
All of the mentioned

All of the mentioned

The Boolean expression X = (A +B)(C+D) represents
Two ORs ANDed together
Two ANDs ORed together
A 4- input OR gate
A 4- input AND gate

F(X,Y,Z) = X`Y`Z`. The degree of the function is __
3
5
4
1

*pending

Complement of the expression A’B + CD’ is _
(A’ + B)(C’ + D)
(A’ + B)(C’ + D’)
(A + B’)(C’ + D)
(A + B’)(C+ D’)

(A + B’)(C’ + D)

The binary equivalent of 28 is
11100
11101
10100
111001

11100

# Practical

## 1.1

If a signal passing through a gate is inhibited by sending a low into one of the inputs, and the output is HIGH, then what kind of gate satisfies the given condition?
NAND
NOT
OR
AND

NAND

The logic gate that will have HIGH or “1” at its output when any one of its inputs is HIGH is a:
OR
AND
NOR
NOT

OR

How many NAND circuits are contained in an HD74LS00 NAND gate IC?
4
6
2
3

4

NOT gate is used as an inverter.
True
False

True

Choose the odd one out
Watch
Calculator
Computer
Coal

Coal

Boolean expression for XNOR gate is
AB + A’B’
AB
A’B’
AB’ + A’B

AB + A’B’

What are the advantages of the digital systems?
High-efficiency
Uses less bandwidth
Encryption
All of the above

All of the above

How many possibilities does two-bit number have?
2
3
4
8

4

The boolean algebra is given by _
George Boole
Pascal
Ronald J Tocci
None of the above

George Boole

All real-life signals are __ in nature
Digital
Analog
Discrete
None of the above

Analog

## 1.2

How many pins does temperature sensor have?
3
2
1
4

3

What is the relation of temperature to resistance in LM35?
linear at 10mv
rising exponential
declining exponential
no effect

*PENDING

The logical product of two or more than two logical sums is termed as
OR operation
POS
SOP
NAND operation

POS

What are the complements used for subtraction?
Binary subtraction
BCD & Excess-3 subtraction
All of the above

All of the above

The Karnaugh map is developed in which year?
1951
1952
1953
1954

1953

What is the output of the temperature sensor?
Temperature
Resistance proportional to the instantaneous temperature
Analog signal proportional to the instantaneous temperature
None of the above

Analog signal proportional to the instantaneous temperature

Who invented Gray code?
Frank Gray
Dom Hofmann
Aryabhatta
None of the above

Frank Gray

__ is used in communication process to minimize the effect of noise.
Digital signal
Analog signal
Electrical signal
None of the above

Digital signal

## 1.3

Exclusive-OR (XOR) logic gates can be constructed from ………..logic gates.
OR gates only
AND gates and NOT gates
AND gates, OR gates, and NOT gates
OR gates and NOT gate

AND gates, OR gates, and NOT gates

……….. truth table entries are necessary for a four-input circuit.
4
8
12
16

16

A radix K number system requires how many different symbols to represent the digits 0 to K – 1?
K
K-1
K+1
1

K

Both OR and AND gates can have only 2 inputs.
True
False

False

……….. input values will cause an AND logic gate to produce a HIGH output.
At least one input is HIGH
At least one input is LOW
All inputs are HIGH
All inputs are LOW

All inputs are HIGH

OR operation is achieved through a NAD gate with additional..
AND gate
OR gate
XOR gate
Inverters

XOR gate

The inputs of a NAND gate are connected together. The resulting circuit is ………….
OR gate
AND gate
NOT gate
None of the above

NOT gate

The only function of NOT gate is to ……………..
Stop signal
Invert input signal
Act as a universal gate
None of the above

Invert input signal

An OR gate has 4 inputs. One input is high and the other three are low. The output is …….
Low
High
Alternately high and low
May be high or low depending on relative magnitude of inputs

High

A single transistor can be used to build ………….. gates .
OR Gate
NOT Gate
AND Gate

NAND Gate

## 1.4

The K-map based Boolean reduction is based on the following Unifying Theorem: A + A’ = 1.
Impact
Non Impact
Force
Complementarity

Non Impact

Product-of-Sums expressions can be implemented using _
2-level OR-AND logic circuits
2-level NOR logic circuits
2-level XOR logic circuits
Both 2-level OR-AND and NOR logic circuits

Both 2-level OR-AND and NOR logic circuits

The Boolean expression Y = (AB)’ is logically equivalent to what single gate?
NAND
NOR
AND
OR

NAND

Four adjacent ‘1’s in a Karnaugh map forms a_______ .
octet
singlet
pair

Each group of adjacent Minterms (group size in powers of twos) corresponds to a possible product term of the given _
Function
Value
Set
Word

Function

If n denotes the number of variable then the number of cells are given as
2n
2+n
2-n
2 to the power of n

2 to the power of n

Using the transformation method you can realize any POS realization of OR-AND with only.
XOR
NAND
AND
NOR

NOR

The prime implicant which has at least one element that is not present in any other implicant is known as _
Essential Prime Implicant
Implicant
Complement
Prime Complement

Essential Prime Implicant

Each “1” entry in a K-map square represents ___
A HIGH for each input truth table condition that produces a HIGH output
A HIGH output on the truth table for all LOW input combinations
A LOW output for all possible HIGH input conditions
DON’T CARE condition for all possible input truth table combinations

A HIGH for each input truth table condition that produces a HIGH output

Which of the following expressions is in the sum-of-products form?
(A + B)(C + D)
(A * B)(C * D)
A* B *(CD)
A * B + C * D

A * B + C * D

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