Combinational Logic Quizzes: Test Your Understanding

Question 1

The Boolean expression for the output of an AND gate with inputs A and B is:

Accepted Answer

A AND B

Answer

A + B

Answer

A - B

Answer

A / B

Question 2

What is the primary function of a NOT gate?

Accepted Answer

To invert the input signal

Answer

To amplify the input signal

Answer

To delay the input signal

Answer

To AND the input signal with itself

Question 3

Which of the following is a characteristic of a digital circuit?

Accepted Answer

It exclusively processes digital signals

Answer

It exclusively processes analog signals

Answer

It can process both analog and digital signals

Answer

It does not process any signals

Question 4

What is the primary purpose of a decoder in a digital logic circuit?

Accepted Answer

To convert a binary code into a specific output signal

Answer

To convert an analog signal into a digital signal

Answer

To amplify a digital signal

Answer

To store digital data

Question 5

Which of the following is a defining property of combinational logic circuits?

Accepted Answer

Their output depends solely on the present inputs

Answer

They have memory and can store data

Answer

They can execute advanced mathematical operations

Answer

They are utilized in analog systems

Question 6

What is the purpose of a multiplexer in a digital logic circuit?

Accepted Answer

To select one of several input signals to pass through to the output

Answer

To amplify a digital signal

Answer

To store digital data

Answer

To convert a binary code into a specific output signal

Question 7

What is the fundamental distinction between a combinational logic circuit and a sequential logic circuit?

Accepted Answer

Sequential logic circuits have memory, whereas combinational logic circuits do not

Answer

Combinational logic circuits have memory, whereas sequential logic circuits do not

Answer

Combinational logic circuits are used in digital computers, while sequential logic circuits are used in analog systems

Answer

Sequential logic circuits are used in digital control systems, whereas combinational logic circuits are used in signal processing

Question 8

An AND gate has two inputs, A and B. What is the output of the AND gate when A = 1 and B = 0?

Accepted Answer

0

Answer

1

Answer

X

Answer

Z

Question 9

Which of the following properties does NOT apply to an Exclusive OR (XOR) gate?

Accepted Answer

Output is 1 when all inputs are 0

Answer

Output is 1 only when one input is 1

Answer

Output is 0 when both inputs are the same

Answer

Output is 1 when both inputs are different

Question 10

What is the main purpose of a decoder in a combinational logic circuit?

Accepted Answer

To generate all possible combinations of outputs for a given number of inputs

Answer

To convert binary code to decimal code

Answer

To convert decimal code to binary code

Answer

To perform arithmetic operations

Question 11

When troubleshooting a combinational logic circuit, what should you do first?

Accepted Answer

Check power supply and connections

Answer

Replace all logic gates

Answer

Measure output at each gate

Answer

Use a logic probe

Question 12

To troubleshoot a malfunctioning combinational logic circuit, what systematic steps should you follow to identify the faulty component(s)?

Accepted Answer

Verify the power supply and input signals meet the circuit's specifications.

Accepted Answer

Test the continuity of all circuit connections using a multimeter to check for open or short circuits.

Answer

Replace all logic gates with new ones, as they are the most likely components to fail.

Question 13

In Boolean algebra, the symbol that represents the logical OR operation is:

Accepted Answer

A + B

Answer

A - B

Answer

~A

Answer

A * B

Question 14

A combinational logic circuit known as a half-adder performs:

Accepted Answer

Addition of two binary digits

Answer

Division of two binary digits

Answer

Subtraction of two binary digits

Answer

Multiplication of two binary digits

Question 15

Which of the following is NOT a type of combinational logic circuit?

Accepted Answer

Sequential circuit

Answer

Adder

Answer

Comparator

Answer

Decoder

Question 16

Which of the following is an advantage of using programmable logic devices (PLDs) for implementing combinational logic circuits?

Accepted Answer

Design flexibility

Answer

Lower cost

Answer

Higher performance

Answer

Reduced power consumption

Question 17

Which of these is NOT a basic logic gate?

Accepted Answer

Flip-flop

Answer

NOT

Answer

AND

Answer

OR

Question 18

What is the output of the logic circuit with the expression: (A AND B) OR (C AND D)?

Accepted Answer

1 (if A and B are both 1, or C and D are both 1)

Answer

0 (if all inputs are 0)

Answer

D

Answer

A

Question 19

Which gate is considered a universal gate?

Accepted Answer

NAND

Answer

NOT

Answer

OR

Answer

AND

Question 20

What is the main function of a decoder circuit?

Accepted Answer

To convert binary code to a specific output signal

Answer

To store data

Answer

To convert decimal code to binary code

Answer

To amplify signals

Question 21

What is the key difference between combinational and sequential logic circuits?

Accepted Answer

Combinational circuits have no memory, while sequential circuits use internal memory to store past input states.

Answer

Combinational circuits are faster than sequential circuits.

Answer

Combinational circuits use less power than sequential circuits.

Question 22

What does a demultiplexer circuit do?

Accepted Answer

It routes a single input signal to one of multiple output lines.

Answer

It amplifies signals.

Answer

It combines multiple input signals into a single output signal.