4.3.3
Boolean Logic
Evaluating Expressions
Evaluating Expressions
Logic gates can be combined to form logic circuits that process complex logical statements such as A AND (B OR C).


Evaluating boolean expressions
Evaluating boolean expressions
- To evaluate a boolean expression, you should substitute all of the values in for the variables and then use the definitions of the different boolean functions to simplify it one step at a time.


Order of evaluation
Order of evaluation
- You should evaluate any expression in brackets first, for example:
- NOT(True OR False).
- NOT(True).
- False.


Truth tables
Truth tables
- Another method of evaluating an expression is using a truth table.
- A truth table shows every possible combination of inputs and the resulting output.
- The truth table shows the input and output state for each combination.
- The table can then be used to look up the output.
Evaluating Expressions
Evaluating Expressions
Logic gates can be combined to form logic circuits that process complex logical statements such as A AND (B OR C).


Evaluating Boolean expressions
Evaluating Boolean expressions
- To evaluate a Boolean expression, you should substitute all of the values in for the variables and then use the definitions of the different Boolean functions to simplify it one step at a time.


Order of evaluation
Order of evaluation
- You should evaluate any expression in brackets first, for example:
- NOT(True OR False).
- NOT(True).
- False.


Truth tables
Truth tables
- Another method of evaluating an expression is using a truth table.
- A truth table shows every possible combination of inputs and the resulting output.
- The truth table shows the input and output state for each combination.
- The table can then be used to look up the output.
1Problem Solving
1.1Algorithms
1.2Decomposition & Abstraction
2Programming
2.1Develop Code
2.2Constructs
2.3Data Types & Structures
2.6Subprograms
3Data
3.2Data Representation
3.3Data Storage & Compression
3.4Encryption
4Computers
4.1Machines & Computational Modelling
4.2Hardware
4.2.1Elements of Computer Systems
4.2.2Types of Computer Systems
4.2.3Memory - RAM
4.2.4Memory - ROM
4.2.5Memory - Cache
4.2.6Running Out of Memory
4.2.7Virtual Memory
4.2.8Magnetic Storage
4.2.9Properties of Magnetic Media
4.2.10Examples of Magnetic Storage
4.2.11Solid State Storage
4.2.12Properties of Solid State Media
4.2.13Optical Storage
4.2.14Properties of Optical Storage
4.2.15Examples of Optical Storage
4.2.16Types of Optical Disk
4.2.17Von Neumann Architecture
4.2.18Registers of the Central Processing Unit (CPU)
4.2.19Fetch-Decode-Execute Cycle
4.2.20Factors Affecting CPU Performance
4.2.21The Cloud
4.2.22How the Cloud Works
4.2.23The Cloud - Pros
4.2.24The Cloud - Cons
4.2.25End of Topic Test - Hardware
4.4Software
5Communication & The Internet
5.1Networks
5.1.1Benefits of Networks
5.1.2Network Performance
5.1.3Types of Network
5.1.4Client-Server Model
5.1.5Pros of Client-Server Model
5.1.6Cons of Client-Server Model
5.1.7Peer-to-Peer Model
5.1.8Pros of Peer-to-Peer Model
5.1.9Cons of Peer-to-Peer Model
5.1.10Network Hardware
5.1.11Transmission Media
5.1.12WiFi
5.1.13WiFi Frequency and Channels
5.1.14WiFi Encryption
5.1.15Network Protocols
5.1.16Transmission Protocols
5.1.17Web Protocols
5.1.18Email Protocols
5.1.19Layers
5.1.20TCP and OSI Models
5.1.21Advantages of Layering
5.1.22Topology - Star
5.1.23Topology - Mesh
5.1.24Topology - Ring
5.1.25Topology - Bus
5.1.26End of Topic Test - Networks
5.2Network Security
6The Bigger Picture
6.1Emerging Trends, Issues & Impact
6.1.1E-Waste
6.1.2Energy Consumption
6.1.3Positive Environmental Impact
6.1.4Ethical Issues - The Digital Divide
6.1.5Ethical Issues - Net Neutrality
6.1.6Ethical Issues - Working Conditions
6.1.7Ethical Issues - Censorship
6.1.8Online Activity Tracking
6.1.9The Internet of Things
6.1.10Positive Cultural Impacts
6.1.11Negative Cultural Impacts
6.1.12Data Protection Act
6.1.13Computer Misuse Act
6.1.14Copyright Designs and Parents Act
6.1.15Creative Commons Licensing
6.1.16Freedom of Information Act
6.1.17Open Source Software
6.1.18Proprietary Software
6.1.19Licensing Issues
6.1.20End of Topic Test - Software & Issues
Jump to other topics
1Problem Solving
1.1Algorithms
1.2Decomposition & Abstraction
2Programming
2.1Develop Code
2.2Constructs
2.3Data Types & Structures
2.6Subprograms
3Data
3.2Data Representation
3.3Data Storage & Compression
3.4Encryption
4Computers
4.1Machines & Computational Modelling
4.2Hardware
4.2.1Elements of Computer Systems
4.2.2Types of Computer Systems
4.2.3Memory - RAM
4.2.4Memory - ROM
4.2.5Memory - Cache
4.2.6Running Out of Memory
4.2.7Virtual Memory
4.2.8Magnetic Storage
4.2.9Properties of Magnetic Media
4.2.10Examples of Magnetic Storage
4.2.11Solid State Storage
4.2.12Properties of Solid State Media
4.2.13Optical Storage
4.2.14Properties of Optical Storage
4.2.15Examples of Optical Storage
4.2.16Types of Optical Disk
4.2.17Von Neumann Architecture
4.2.18Registers of the Central Processing Unit (CPU)
4.2.19Fetch-Decode-Execute Cycle
4.2.20Factors Affecting CPU Performance
4.2.21The Cloud
4.2.22How the Cloud Works
4.2.23The Cloud - Pros
4.2.24The Cloud - Cons
4.2.25End of Topic Test - Hardware
4.4Software
5Communication & The Internet
5.1Networks
5.1.1Benefits of Networks
5.1.2Network Performance
5.1.3Types of Network
5.1.4Client-Server Model
5.1.5Pros of Client-Server Model
5.1.6Cons of Client-Server Model
5.1.7Peer-to-Peer Model
5.1.8Pros of Peer-to-Peer Model
5.1.9Cons of Peer-to-Peer Model
5.1.10Network Hardware
5.1.11Transmission Media
5.1.12WiFi
5.1.13WiFi Frequency and Channels
5.1.14WiFi Encryption
5.1.15Network Protocols
5.1.16Transmission Protocols
5.1.17Web Protocols
5.1.18Email Protocols
5.1.19Layers
5.1.20TCP and OSI Models
5.1.21Advantages of Layering
5.1.22Topology - Star
5.1.23Topology - Mesh
5.1.24Topology - Ring
5.1.25Topology - Bus
5.1.26End of Topic Test - Networks
5.2Network Security
6The Bigger Picture
6.1Emerging Trends, Issues & Impact
6.1.1E-Waste
6.1.2Energy Consumption
6.1.3Positive Environmental Impact
6.1.4Ethical Issues - The Digital Divide
6.1.5Ethical Issues - Net Neutrality
6.1.6Ethical Issues - Working Conditions
6.1.7Ethical Issues - Censorship
6.1.8Online Activity Tracking
6.1.9The Internet of Things
6.1.10Positive Cultural Impacts
6.1.11Negative Cultural Impacts
6.1.12Data Protection Act
6.1.13Computer Misuse Act
6.1.14Copyright Designs and Parents Act
6.1.15Creative Commons Licensing
6.1.16Freedom of Information Act
6.1.17Open Source Software
6.1.18Proprietary Software
6.1.19Licensing Issues
6.1.20End of Topic Test - Software & Issues
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