Unit 2 (DE)

                     

Theory

Quiz 1

What is the function of an enable input on a multiplexer chip?
to apply Vcc
to connect ground
to active the entire chip
to active one half of the chip

to active the entire chip

The flip flops are activated by _ trigger
Only positive edge
Only negative edge
Either positive or negative edge
None of the above

Either positive or negative edge

The combinational circuit have __ number of stable states
1
2
3
4

2

When the clock input is low in a D flip flop then the input of the D flip flop is________
High
LOW
No Effect
None of the above

No Effect

In a comparator, if we get input as A>B then the output will be __
1
0
A
B

1


Quiz 2

When toggle condition occurs in JK flip flop?
J=1, K=1
J=0, K=0
J=1, K=0
J=0, K=1

J=1, K=1

When reset is high and set is low in a NOR D-latch table then the output will be __
No change
High
Low
Invalid

Low

The shift registers are categorized into ________types.
1
2
3
4

4


Surprise Test

The output of a sequential circuit depends on _.
only its input
only its state
its states and input
Decision of the designer

its states and input

Who invented first flip flop?
F.W. Jordan
William Eccles
Harald
Both a and b

Both a and b

The flip flop requires _
More number of gates
More power
Both a and b
None of the above

Both a and b

When reset is high and set is low in a NOR D-latch table then the output will be __
No change
High
Low
Invalid

Low

How many inputs does the RS latch have?
One input
Two inputs
Three inputs
Four inputs

Two inputs

There are total __ steps for flip flop conversions
1
2
4
5

5

When toggle condition occurs in JK flip flop?
J=1, K=1
J=0, K=0
J=1, K=0
J=0, K=1

J=1, K=1

The flip flop is a _ device.
Unstable
Bi-stable
Both a and b
None of the above

Bi-stable

How many inverters does the basic latch consists of?
1
2
3
4

2

The shift registers are categorized into ________types.
1
2
3
4

4

The flip flops works with __
Binary inputs
Clock signal
Both a and b
None of the above

Both a and b

How many possible conversions are there to convert SR flip flop to other flip flops?
1
2
3
4

3


Practical

2.1

If A, B and C are the inputs of a full adder then the carry is given by __
A AND B OR (A OR B) AND C
A OR B OR (A AND B) C
(A AND B) OR (A AND B)C
A XOR B XOR (A XOR B) AND C

A AND B OR (A OR B) AND C

How many AND, OR and EXOR gates are required for the configuration of full adder?
1, 2, 2
2, 1, 2
3, 1, 2
4, 0, 1

2, 1, 2

Half-adders have a major limitation in that they cannot __
Accept a carry bit from a present stage
Accept a carry bit from a next stage
Accept a carry bit from a previous stage
Accept a carry bit from the following stages

Accept a carry bit from a previous stage

In parts of the processor, adders are used to calculate __
Addresses
Table indices
Increment and decrement operators
All of the Mentioned

All of the Mentioned

In which operation carry is obtained?
Subtraction
Addition
Multiplication
Both addition and subtraction

Addition

The difference between half adder and full adder is __
Half adder has two inputs while full adder has four inputs
Half adder has one output while full adder has two outputs
Half adder has two inputs while full adder has three inputs
All of the Mentioned

Half adder has two inputs while full adder has three inputs


2.2

Two input MUX have_________ select lines.
1
2
3
4

1

MUX is also known as
Coder
Parallel Adder
Data Selector
Gates

Data Selector

What is the expression for the sum(s) of a half adder if the inputs are A & B?
S = A OR B
S = A AND B
S = A XNOR B
S = A XOR B

S = A XOR B

While implementing NOT gate using 2:1 MUX, the two inputs will be_________
A=0 & B=1
A=1 & B=1
A=0 & B=0
A=1 & B=0

A=1 & B=0

To implement NOR gate using MUX, ___ 2:1 will be required.
2
3
4
5

2

If enable input is high then MUX is __
Enable
Disable
Saturation
High Impedance

Disable


2.3

Which method of combination circuit implementation is widely adopted with maximum output functions and minimum requirement of ICs?
Multiplexer Method
Decoder Method
Encoder Method
Parity Generator Method

Decoder Method

Why are the lines specifically used for connecting two or more IC packages in accordance to its application in decoder circuit?
It allows the reduction of digital function into similar function with more inputs & outputs
It allows the expansion of digital function into similar function with more inputs & outputs
It allows the reduction of digital function into different function with more inputs & outputs
It allows the expansion of digital function into different function with more inputs & outputs

It allows the expansion of digital function into similar function with more inputs & outputs

Which of the following represents a number of output lines for a decoder with 4 input lines?
15
16
17
18

16

Decoders and Encoders are doing the reverse operation?
True
False

True

A decoder can be used as a demultiplexer by?
tying all enable pins LOW
tying all data-select lines LOW
tying all data-select lines LOW
using the input lines for data selection and an enable line for data input

using the input lines for data selection and an enable line for data input

The input at the 1, 2, 4, 8 inputs to a 4-line to 16-line decoder with active-low outputs is 1110. As a result, output line 7 is driven LOW?
True
False

False


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