Boolean Logic Whats it all about Lesson Objectives

Boolean Logic What's it all about?

Lesson Objectives �All must know the three basic logic gate operators �Most should be able to utilise the truth table to work out the output of given inputs �Some could explain the use of Truth Tables for working-out the output of an input combination.

Why would I want to learn this? Boolean logic is used everywhere. �We use it all the time when we make decisions. �It is used a lot in computer programming for example; computer games

How do computers do it? Just a few decades ago only humans could do things like Drive a car Play chess Spell check a document

What’s this Boole thing? George Boole was an English Mathematician, who came up with a way of writing down logic. But what is logic? Logic is a way of defining truth. 1815 - 1864

What do I need to know? There are only a few rules you need to know. In logic the main choices are… AND OR NOT

Making Decisions �Life if full of decisions �What decisions have you made today?

Task 1 – Fill in the gaps… I get the plane NOT the bus to Australia I will have chips OR rice with my kebab. The car uses diesel OR petrol. I need pens AND paper for school Use Sugar NOT salt in my tea.

What are Logic Gates? �They are electronic devices that use signals as their inputs. �The inputs and outputs from a gate are either: On 1 or Off 0

Logic Gates �There are 3 main types which match the Boolean statements we have just been talking about: AND OR NOT

AND Gate A B Q The output is on if both the inputs are on. For example if the inputs are 1 and 1 the output will be 1 What would the output be if the inputs are 1 and 0?

OR Gate A Q B The output is on if either of the inputs are on. For example if the inputs were 0 and 1 the output will be 1 What would the output be if the inputs are 1 and 0?

NOT Gate Q A Whatever the input is the output is always the opposite. For example: if the input is 1 the output will be 0 What would the output be if the input is 0?

How to Remember N + D joined together O + R joined together Looks like a extended D Looks like a spaceship ND OR

Logic Gate Summary AND OR A Q B A B The output is on if both the inputs are on. The output is on if either of the inputs are on. NOT Q Q A Whatever the input is the output is always the opposite.

Task 2 – Fill in the missing Values 0 1 0 1 0 0 0 1 1

Putting them together �The AND, OR and NOT gates are combined to produce logic diagrams. �These diagrams follow the same rules as individual gates. Don’t let the combination of different gates scare you off!

Task 3 - Example 0 0 0 Now download Worksheet 2 from this link: Ict 4 u. net/Computer. Science/includes/Bool ean-Logic-Worksheet 2. DOCX

Worksheet 2 Now download Worksheet 2 from this link: http: //bit. ly/2 SYfec 1 Or Ict 4 u. net/Computer. Science/includes/ Boolean-Logic-Worksheet 2. DOCX

Keywords � Boolean A datatype in computing which only has two possible values, true or � � false. Truth Table Used to assess possible results of a Boolean algebra statement. Logic Gate Circuit components which take several inputs, compare the inputs � � � with each other, and provide a single output based on logical functions such as AND, OR and NOT. Input A variable (typically A, B and C) to represent a value, either 1 or 0. Output A variable (typically P ) to represent a value, either 1 or 0. Variable In a computer program, this is a memory location where values are stored.

Writing Boolean Expressions Expression Written as Alternative AND A∧B A. B OR A∨B A+B NOT X ¬x

Plenary