Combining Boolean Operators (AQA GCSE Computer Science)
Revision Note
Written by: Robert Hampton
Reviewed by: James Woodhouse
Combining Boolean Operators
Boolean operators can be combined to produce more complex expressions
The combination of two or more Boolean operators forms a logic expression
Brackets are used to clarify the order of operations
A logic diagram is a visual representation of combinations of Boolean operators within a logic circuit
An example would be Q = NOT(A OR B) //
In the diagram above, the inputs are represented by A and B
P is the output of the OR gate on the left and becomes the input of the NOT gate
Q is the final output of the logic circuit
This is a logic diagram for the Boolean expression Q = NOT(A OR B) //
Examiner Tips and Tricks
You may be asked to draw a logic circuit from a logic statement or a Boolean expression OR write the logical expression that is expressed in the logic diagram using Boolean expression operators
Logic circuits will be limited to a maximum of three inputs and one output
Example of combining Boolean operators
P = (A OR B) AND NOT C //
Worked Example
A green light (G) in a game switches on if all of the following conditions are true:
sensor D is off
sensor L is off
sensor W is on
Write a Boolean expression for this logic circuit.
You must use Boolean expression operators in your answer [3]
Answer
D̅. L̅. W // (D̅. W). (L̅. W)
Guidance
2 marks if fully correct but using different notation, e.g. NOT D AND NOT L AND W
Last updated:
You've read 0 of your 10 free revision notes
Unlock more, it's free!
Did this page help you?