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Worksheets

Combinational Circuits

Total questions: 20

Worksheet time: 11mins

Name
Class
Date
1.

What is the function of an AND gate?

a)

The function of an AND gate is to output true only when all inputs are true.

b)

The function of an AND gate is to output true when at least one input is true.

c)

The function of an AND gate is to output false only when all inputs are false.

d)

The function of an AND gate is to output true regardless of the input values.

2.

How does a NOT gate operate on its input?

a)

A NOT gate outputs the opposite of its input.

b)

A NOT gate adds a value to its input.

c)

A NOT gate only works with binary inputs.

d)

A NOT gate outputs the same as its input.

3.

What is the output of a NAND gate when both inputs are true?

a)

true

b)

high

c)

false

d)

undefined

4.

Define a multiplexer and its primary function.

a)

A multiplexer is a device that selects one of multiple input signals and outputs it.

b)

A multiplexer is a device that amplifies signals.

c)

A multiplexer is a device that stores data temporarily.

d)

A multiplexer is used to convert analog signals to digital.

5.

What is the difference between a multiplexer and a demultiplexer?

a)

A multiplexer distributes one input to multiple outputs, while a demultiplexer combines multiple inputs into one output.

b)

A multiplexer combines multiple inputs into one output, while a demultiplexer distributes one input to multiple outputs.

c)

A multiplexer and a demultiplexer perform the same function of routing signals.

d)

A multiplexer is used only in digital circuits, while a demultiplexer is used in analog circuits.

6.

How many select lines are needed for a 4-to-1 multiplexer?

a)

2

b)

1

c)

3

d)

4

7.

What is the purpose of an adder in digital circuits?

a)

To convert binary to decimal.

b)

The purpose of an adder is to perform binary addition.

c)

To store binary data.

d)

To perform binary subtraction.

8.

Explain the difference between a half adder and a full adder.

a)

A half adder adds two bits, while a full adder adds three bits (including carry-in).

b)

A half adder adds two bits, while a full adder adds two bits.

c)

A half adder is used for decimal addition, while a full adder is used for binary addition.

d)

A half adder can handle carry-in, while a full adder cannot.

9.

What is the function of a subtractor in combinational circuits?

a)

The function of a subtractor is to perform subtraction of binary numbers.

b)

The function of a subtractor is to compare two binary numbers.

c)

The function of a subtractor is to perform addition of binary numbers.

d)

The function of a subtractor is to convert binary numbers to decimal.

10.

Define an encoder and its role in digital systems.

a)

An encoder translates coded output back into input signals.

b)

An encoder amplifies input signals for better transmission.

c)

An encoder stores data in a physical format for backup.

d)

An encoder converts input signals into a coded output in digital systems.

11.

What is the primary function of a decoder?

a)

The primary function of a decoder is to convert encoded data back into its original format.

b)

To encrypt data for security

c)

To compress data for storage

d)

To transmit data over networks

12.

How does a 2-to-4 decoder work?

a)

A 2-to-4 decoder activates all outputs simultaneously regardless of input.

b)

A 2-to-4 decoder only works with binary inputs of 3 bits.

c)

A 2-to-4 decoder converts 4 input bits into 2 unique output lines.

d)

A 2-to-4 decoder converts 2 input bits into 4 unique output lines, activating one output based on the input combination.

13.

What is a comparator used for in digital electronics?

a)

A comparator is used to compare two voltages or currents and output a digital signal indicating which is larger.

b)

A comparator is used to convert analog signals to digital signals.

c)

A comparator is used to store data in memory.

d)

A comparator is used to amplify signals before processing.

14.

Explain the difference between sequential and combinational circuits.

a)

Sequential circuits are faster than combinational circuits.

b)

Sequential circuits operate without any feedback loops.

c)

Combinational circuits can store data while sequential circuits cannot.

d)

Sequential circuits store past states; combinational circuits do not.

15.

What is the significance of propagation delay in combinational circuits?

a)

Propagation delay is significant as it impacts the speed and performance of combinational circuits.

b)

Propagation delay is a measure of power consumption.

c)

Propagation delay is irrelevant in digital circuits.

d)

Propagation delay only affects analog circuits.

16.

How can you implement a logic function using only NAND gates?

a)

You can implement any logic function using combinations of NAND gates to create NOT, AND, and OR gates.

b)

You can only use NAND gates to create NOT gates.

c)

You need at least one AND gate to implement any logic function.

d)

NAND gates cannot be used to implement OR functions.

17.

What is the truth table for a XOR gate?

a)

| A | B | A XOR B | |---|---|---------| | 0 | 0 | 0 | | 0 | 1 | 1 | | 1 | 0 | 1 | | 1 | 1 | 1 |

b)

| A | B | A XOR B | |---|---|---------| | 0 | 0 | 0 | | 0 | 1 | 1 | | 1 | 0 | 1 | | 1 | 1 | 0 |

c)

| A | B | A XOR B | |---|---|---------| | 0 | 0 | 1 | | 0 | 1 | 0 | | 1 | 0 | 0 | | 1 | 1 | 1 |

d)

| A | B | A XOR B | |---|---|---------| | 0 | 0 | 1 | | 0 | 1 | 1 | | 1 | 0 | 0 | | 1 | 1 | 0 |

18.

Describe the role of a priority encoder.

a)

A priority encoder converts binary code into decimal format.

b)

A priority encoder amplifies signals from multiple sources.

c)

A priority encoder converts multiple active inputs into a binary code representing the highest priority input.

d)

A priority encoder selects the lowest input signal for output.

19.

What is the output of a 3-bit comparator when both inputs are equal?

a)

0

b)

1

c)

3

d)

2

20.

How do combinational circuits differ from sequential circuits in terms of memory?

a)

Sequential circuits do not use memory elements at all.

b)

Combinational circuits lack memory, while sequential circuits have memory elements.

c)

Both combinational and sequential circuits have the same memory capabilities.

d)

Combinational circuits have more memory than sequential circuits.