1. Unit 1
Logical operators

2. Assessment Outcomes 4G Logical operations
4H Truth tables using up to 3 logical operations

3. Learning Intentions and Outcomes
Learning Intention: To develop an understanding of the NOT, AND, OR, and XOR Logic gates
Grade Pass
Use AND, OR, NOT and XOR logical operators to create simple truth tables
Grade Merit
Combine logic gates to create logic circuits and filling in appropriate truth tables
Analyse logic circuits to calculate an output, creating appropriate truth tables
Grade Distinction
Complete truth tables for standard logic circuits without the use of diagrams
Combine 8 bit registers using standard logic operators

4. 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?
What is the difference between an AND and a NAND 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?

5. Thinking Task
What can you tell me about this?

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

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

8. Thinking Task

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

10. 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

11. 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)

12. 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

13. 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

14. 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

15. 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

16. Binary Logic – NAND Gate
If both inputs are 1 then the output is 0
Otherwise the output is 1
It is the polar opposite of an AND gate! A B P 1
INPUT A B
OUTPUT P
Boolean Algebra: P = A AND B
Truth Table
Logic Diagram

17. Task Grade Pass Exercises
Complete the Grade Pass Exercises
Extension:
The extension task asks you to combine multiple logic gates. Have a look at slides to help you with this.

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

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

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

21. Combining Logic Gates WHAT GATE IS THIS? Boolean Algebra:
P = NOT (A AND B)

22. Activity: Combined Logic Operators worksheet
Draw a logic circuit of your own design that has at least 3 logic gates. You should also draw a truth table and write the Boolean algebra expression. 1

23. Graded Exercises Complete the Grade Merit and Distinction exercises
You can use the pre-reading, PowerPoint, Internet to help you
Grade Distinction* Extension:
Check out the websites to learn a little more about how Logic Gates work
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!

24. 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!

25. Homework Pre-Reading Notes: Low and High level programming languages
Exercises:
Complete the Merit level exercises