8 - Logic Gates - Improved

Logic Gates
Pens, pencils and paper needed
1 / 21
Slide 1: Slide
ComputingUpper Secondary (Key Stage 4)GCSE

This lesson contains 21 slides, with interactive quizzes and text slides.

Items in this lesson

Logic Gates
Pens, pencils and paper needed

Slide 1 -Slide

Can you remember the three main logic gates?

Slide 2 -Open question

Key Objective: To gain undetstanding of boolean logic and Logic Gates.
All: Know the Main three logic gates, their symbols and truth tables.

Most: Understand some simple logic gate problems.

Some: Understand more complex problem solving with logic gates.

Slide 3 -Slide

Anatomy of a logic gate

Slide 4 -Slide

Truth Table: AND
Copy down the symbol and table
Input A
Input B
Output
0
0
0
1
1
0
1
1

Slide 5 -Slide

AND gate with two inputs.
Input A = 1, Input B = 0
What is the output?
A
1
B
0

Slide 6 -Quiz

AND gate with 3 inputs.
Input A = 1, Input B = 1, Input C = 0
What is the output?
A
1
B
0

Slide 7 -Quiz

Truth Table: OR
Copy down the symbol and table
Input A
Input B
Output
0
0
0
1
1
0
1
1

Slide 8 -Slide

OR gate with 2 inputs.
Input A = 0, Input B = 0
What is the output?
A
1
B
0

Slide 9 -Quiz

OR gate with 3 inputs.
Input A = 0, Input B = 0, Input C = 1
What is the output?
A
1
B
0

Slide 10 -Quiz

OR gate with 2 inputs.
Input A = 1, Input B = 1
What is the output?
A
1
B
0

Slide 11 -Quiz

Truth Table: NOT

Copy down the symbol and table
Input A
Output
0
1

Slide 12 -Slide

Logic Gate Expressions
a AND (NOT b)
a
b
Output
0
0
1
0
0
1
1
1

Slide 13 -Slide

Open Logic.ly here
Draw
(a OR b) AND (NOT c)
with logic gates:

Slide 14 -Slide

(a OR b) AND (NOT c)

Now, draw the truth table.

Slide 15 -Slide

(a OR b) AND (NOT c)
A
B
C
Output
0
0
0
0
0
1
0
1
0
1
0
0
0
1
1
1
0
1
1
1
0
1
1
1

Slide 16 -Slide

NAND gates
NOR gates
XOR gates

Create with logic.ly a drawing using all three of these, and write the truth table for it.

Slide 17 -Slide

Which Logic gate is this?
A
AND
B
OR
C
NOT

Slide 18 -Quiz

Which Logic gate is this?
A
AND
B
OR
C
NOT

Slide 19 -Quiz

Which Logic gate is this?
A
AND
B
OR
C
NOT

A
1
B
0