Logic Circuits - SS2 ICT Past Questions and Answers - page 2
What is the output of an OR gate if all its inputs are 0?
0
1
Cannot determine
Depends on the number of inputs
Which logic gate's output is the inverse of the AND gate's output?
NAND gate
XNOR gate
XOR gate
NOR gate
In a digital circuit, which gate would you use to select one input from multiple sources?
AND gate
OR gate
XOR gate
Multiplexer
Which logic gate's symbol resembles a curved "D" shape?
AND gate
OR gate
XOR gate
NOT gate
Explain the behavior of an XOR gate using truth tables
An XOR gate, or Exclusive OR gate, produces an output of 1 when the number of input signals that are 1 is odd. In other words, the output is 1 when the inputs are different. The truth table for an XOR gate is as follows:
|
Input A |
Input B |
Output |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
0 |
1 |
|
1 |
1 |
0 |
How can NAND gates be used to construct any other type of logic gate?
NAND gates are versatile and can be used to create all other types of logic gates. This property is known as functional completeness. By properly connecting the inputs and outputs of NAND gates, you can implement the behavior of AND, OR, NOT, XOR, and other gates. This is achieved through a combination of inputs and inversion of signals using multiple NAND gates.
Provide an example of a real-world application that utilizes logic gates.
One real-world application of logic gates is in computer memory systems. Logic gates are used in the design of flip-flops and registers, which store binary data in digital systems. These components are essential for storing temporary data, enabling sequential logic, and managing data flow within a computer's memory hierarchy.
Describe the purpose of a multiplexer in digital circuits.
A multiplexer, often referred to as a "mux," is a digital circuit that allows you to select one out of multiple input signals and route it to a single output line. It acts like a data selector. Multiplexers are commonly used in digital systems for tasks such as data routing, signal switching, and selecting inputs to a processor or memory module. They are particularly useful in managing data paths and controlling which input gets processed or passed through to the output.