Component 1 Logical operators

Starter Pre-Reading Recap What is a logic gate? What is the difference between a not gate and an or gate? What does an XOR gate do? What does an AND gate do? Describe how an OR gate works How many Inputs can a logic gate have? What happens when you combine an AND and a NOT gate? If I have a 1 and a 0 pass through an AND gate what is the output? If I have a 1 and a 0 pass through a Not gate what is the output? If I have a 1 and a 0 pass through an OR gate what is the output?

Learning Intentions and Outcomes Learning Intention: To develop an understanding of the NOT, AND, OR, and XOR Logic gates Use AND, OR, NOT and XOR logical operators, combinations of these, and their application in appropriate truth tables to solve problems

Thinking Task What can you tell me about this?

Thinking Task What can you tell me about this? If there are CLOUDS and COLD there will be RAIN

Thinking Task What can you tell me about this? If A and B are TRUE then Q is TRUE

Thinking Task

Thinking Task Q=1 when A is not 1 Only 1 and 1 = 1 1 and 0 = 0 (or does not = 1)

Logical operators - Binary Why is binary so important? Fundamentally computers are electronic and can decide between two states – true or false, on or off, presence or absence of current and translate this into the binary representation of 1 or 0

Binary Logic As computers use transistors and capacitors to store binary data we can wire them together to make simple logical calculations These simple circuits are known as logic gates There are four fundamental gates you know need to know about: NOT gate AND gate OR gate XOR gate (Exclusive OR gate)

Boolean Algebra: P = NOT A Binary Logic – Not Gate If 0 is input it outputs 1 If 1 is input it outputs 0 INPUT A OUTPUT P Boolean Algebra: P = NOT A Logic Diagram

Boolean Algebra: P = A AND B Binary Logic – AND Gate If both inputs are 1 then the output is 1 Otherwise the output is 0 INPUT A B OUTPUT P Boolean Algebra: P = A AND B Logic Diagram

Boolean Algebra: P = A OR B Binary Logic – OR Gate If either input is 1 then the output is 1 Otherwise the output is 0 INPUT A B OUTPUT P Boolean Algebra: P = A OR B Logic Diagram

Boolean Algebra: P = A xOR B Binary Logic – XOR Gate If either input is 1 then the output is 1 UNLESS! Both are 1! Otherwise the output is 0 INPUT A B OUTPUT P Boolean Algebra: P = A xOR B Logic Diagram

Activity In your books draw the diagrams and truth tables for the following Logic Gates: Not AND OR XOR Make sure to label the inputs and outputs. It is always a good idea to put an example of your logic gate in use for your diagram.

Combining Logic Gates We can string logic gates together to make more complex circuits Boolean Algebra: P = NOT (A AND B)

Combining Logic Gates We can string logic gates together to make more complex circuits Boolean Algebra: P = NOT (A AND B)

Combining Logic Gates We can string logic gates together to make more complex circuits Boolean Algebra: P = NOT (A AND B)

Activity: Combined Logic Operators worksheet Complete the ‘combined logic operators’ worksheet This can be found in today’s lesson folder. 1

Graded Exercises You must complete the grade 4 exercises before you move on. You can use the pre-reading, PowerPoint, Internet, or the Help! Folder to help you complete the grade 4 exercises. When you have completed grade 4 you can move on to the grade 5-8 exam questions. (You will need to print these). Remember to be smart when using the Internet: Wikipedia is often complicated – sometimes even I don’t understand! BBC Bitesize, Teach ICT, and Revision World are better places to find your information!

Crib Sheet – What I must remember about ___ Starting Point: Read the learning outcomes from the exam board Record the key facts that you need to remember about Logical Operators! Think about what you have learnt today, what questions you have been asked, definitions of words, or anything else you think is important!

Homework Question Sheets: 7 Logic Gates Pre-reading notes: Pages 21-22