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Logic Gates lesson 1 Flipbook PDF
Logic Gates lesson 1
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Logic Statements
Classroom Expectations No Talking
No Calling Out
No Standing
Eyes on Screen
P – Professional P – Polite P – Punctual
Lesson Objective All can identify and the different logic statements Most can complete Truth Tables to show the result of different logic statements
Some can identify different logic gates
Logic Statement (True or False) Logic in computers has 2 values These are TRUE (1) and FALSE (0).
A logic statement or question will always have one of these answers
Starter Activity 1 (True or False) For each of the statements below, decide whether the answer will be True (1) or False (0) Condition It is January Today is Friday Today is Not Monday It is March
True or False?
Boolean Logic Boolean Logic combines different Logic statements but always gives and answer that is TRUE or FALSE
Boolean Logic uses operators (just like in maths) Three of the most common Boolean Operators are: AND, OR and NOT
We can use Boolean operators to put together more complicated logic statements and tests For Example:
It is March AND it has been raining You can serve coffee black OR white Out is the same as NOT in
Activity 2 (use 1 or 0) For the statements below, use 1 for True and 0 for False- there is more then on condition to check Condition A
Condition B
Today is Easter
It is January
Today is not Friday
It is March
Today is School day
It is February
Today is Friday
It is March
True or False?
True or False?
A
B
A & B are True
1
1
1
Activity 3 • On your worksheet, write a statement using each of the operators Make sure the statement can be answer TRUE or FALSE! AND. __________________________________________________________ OR. __________________________________________________________ NOT. __________________________________________________________
How do Computers use Logic? A computer consist of millions with circuits, each of which can be ON or OFF A computer does different tasks by turning different circuits ON or OFF There are millions of combinations of circuits that can be triggered, and the computer uses Logic to decide what different combinations mean
Light Circuit • Looking at the simple light circuit below: • If the switch is open or OFF, the light is off • If the switch is closed or ON, the light is on
Truth Table There can be multiple switches in a circuit and the end result can be different depending in which switches are ON and which are OFF
We record the results in a tabular format called TRUTH TABLE Using our light circuit as example, we can see that the switch can be on or off and the bulb can be on or off.
Truth Table A
Q
ON
ON
The table shows the different values for the switch (A) and the bulb (Q) If the switch is ON, the bulb is ON
Truth Table A
Q
ON
ON
OFF
OFF
The table shows the different values for the switch (A) and the bulb (Q) If the switch is ON, the bulb is ON If the switch is OFF the bulb is OFF
AND Circuit Sometimes a circuit could have more than one switch In this circuit both switches must be ON for the bulb to be ON
Activity 4 – AND Circuit On your worksheet, complete the truth table for this circuit
Remember: Switch ‘A’ AND Switch ‘B’ have to be ON for the bulb to glow
Think about the different combinations of ON and OFF for the switches
A
B
OFF
OFF
Q
OR Circuit This circuit also has two switches They run in Parallel though This means that only one must be ON for the bulb to glow
Activity 5 – OR Circuit On your worksheet, complete the truth table for this circuit
Remember: Switch ‘A’ OR Switch ‘B’ must be ON for the bulb to glow
Think about the different combinations of ON and OFF for the switches
A
B
OFF
OFF
Q
What is Logic Gate ? When we draw an electronic circuit we don't actually draw pictures of batteries, switchs and bulbs
In a electronic, each of these circuits we have looked at, is called a Logic GATE Each Logic Gate has its own special symbol Each Logic Gate has a truth table that can show how the GATE works
Logic Gate Symbols
AND Logic Gate The AND Gate, has at least two inputs The output is TRUE when ALL of the input conditions are TRUE. Out is equal to A AND B
A 0 0 1 1
B 0 1 0 1
Out (A and B) 0 0 0 1
Truth Table
OR Logic Gate The OR Gate, has at least two inputs The output is TRUE when one OR more of the input conditions are TRUE Out is equal to A OR B
A 0 0 1 1
B 0 1 0 1 Truth Table
Out (A or B) 0 1 1 1
NOT Logic Gate Imagine a circuit which worked the opposite way to the way you would expect When the switch Is ON the light is OFF When the switch is OFF the light is ON A 0 1 Truth Table
Out 1 0
Plenary • What we learned • What are logic statements • What is Truth Table • Symbols of basic Logic Gates
Do the following Fill the activity Sheet S:\!Creative Technologies\ICT\Mr Rehman\Year 7\Lesson 1\Activity Sheet.docx Fill the feedback Sheet S:\!Creative Technologies\ICT\Mr Rehman\Year 7\Lesson 1\feedback.docx Type Socrative.com in the web browser Login as Student
Room No: SAM9155