Electronics - SS2 Physics Past Questions and Answers - page 5
What is the output of a NAND gate when all of its inputs are HIGH (logic level 1)?
LOW (logic level 0)
HIGH (logic level 1)
It depends on the number of inputs.
Cannot be determined.
Explain the operation and truth table of a 4-input NAND gate. Provide an example of a practical application where a 4-input NAND gate can be used.
A 4-input NAND gate is a logic gate that produces an output of logic level 0 (LOW) only when all of its inputs are at logic level 1 (HIGH). The truth table for a 4-input NAND gate is as follows:
|
A |
B |
C |
D |
Y |
|
0 |
0 |
0 |
0 |
1 |
|
0 |
0 |
0 |
1 |
1 |
|
0 |
0 |
1 |
0 |
1 |
|
0 |
0 |
1 |
1 |
1 |
|
1 |
1 |
1 |
1 |
0 |
One practical application of a 4-input NAND gate is in digital circuits where the output should be HIGH only when multiple conditions are met simultaneously. For example, in a security system, if multiple sensors need to be triggered for an alarm to activate, a 4-input NAND gate can be used to combine the sensor outputs. The alarm will sound only when all the sensors detect an intrusion.
Describe the operation and truth table of a 2-input XOR gate. Discuss the significance of XOR gates in digital logic circuits.
A 2-input XOR gate is a logic gate that produces an output of logic level 1 (HIGH) when the number of inputs at logic level 1 is odd. The truth table for a 2-input XOR gate is as follows:
|
A |
B |
Y |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
0 |
1 |
|
1 |
1 |
0 |
XOR gates are significant in digital logic circuits because they are used for several purposes. Firstly, XOR gates are fundamental building blocks for constructing other types of gates, such as XNOR gates and half-adders. Secondly, XOR gates are widely used in error detection and correction circuits, such as parity checkers. Additionally, XOR gates are employed in data encryption and decryption algorithms, where they play a crucial role in the generation of cryptographic keys.
Explain the concept of a multiplexer (MUX) and its operation. Provide an example of a practical application where a multiplexer can be used.
A multiplexer, or MUX, is a digital device that allows multiple inputs to be selectively routed to a single output based on control signals. It is often referred to as a data selector. A multiplexer consists of two main components: the data inputs and the control inputs. The control inputs determine which data input is passed through to the output.
The operation of a multiplexer can be explained using a 4-to-1 MUX as an example. A 4-to-1 MUX has four data inputs, one output, and two control inputs. The control inputs, typically denoted as S0 and S1, select one of the four data inputs to be routed to the output. The selection is based on the binary value of the control inputs.
A practical application of a multiplexer is in digital communication systems. For example, in a telephone system, a multiplexer is used to combine multiple voice signals from different callers into a single transmission line, allowing efficient use of the available bandwidth. The control inputs of the multiplexer determine the caller whose voice signal is being transmitted
Integrated circuits (ICs) are widely used in electronic devices because they:
Provide high-speed data transfer
Increase the physical size of the device
Enhance the durability of the device
Integrate multiple electronic components onto a single chip
Which of the following is NOT an advantage of integrated circuits?
Reduced size and weight of electronic devices
Lower power consumption
Higher manufacturing costs
Improved reliability and performance
The basic building block of an integrated circuit is:
Transistor
Resistor
Capacitor
Diode
Which type of integrated circuit is commonly used for storing digital information?
Operational amplifier (Op-amp)
Microprocessor
Digital-to-analog converter (DAC)
Random access memory (RAM)
The term "VLSI" stands for:
Very Large Scale Integration
Variable Logic System Integration
Voltage Level Sensing Interface
Visible Light Spectrum Illumination
Which of the following is NOT a category of integrated circuits based on their complexity?
Small Scale Integration (SSI)
Medium Scale Integration (MSI)
Large Scale Integration (LSI)
Ultra Large Scale Integration (ULSI)