Boolean Logic Diagrams (Edexcel GCSE Computer Science)

What is Boolean logic?

• Boolean logic is used in computer science and electronics to make logical decisions

• Boolean operators are either TRUE or FALSE, often represented as 1 or 0

• Inputs and outputs are given letters to represent them

• To define Boolean logic we use special symbols to make writing expressions much easier 

AND Gates, OR Gates & NOT Gates

What are logic gates?

• Logic gates are a visual way of representing a Boolean expression

• The logic gates covered in this course are:

  • AND

  • OR

  • NOT

AND

Circuit symbol	Explanation
	Returns TRUE only if both inputs are TRUE  TRUE AND TRUE = TRUE Otherwise = FALSE

OR

Circuit symbol	Explanation
	Returns TRUE if either input is TRUE  TRUE OR FALSE = TRUE  FALSE OR FALSE = FALSE

NOT

Circuit symbol	Explanation
	Reverses the input value NOT TRUE = FALSE NOT FALSE = TRUE