# Logic Gates V4

Logic Gates
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Slide 1: Slide
ComputingLower Secondary (Key Stage 3)

This lesson contains 33 slides, with interactive quizzes and text slides.

Lesson duration is: 50 min

## Items in this lesson

Logic Gates

#### Slide 1 -Slide

KO: Demonstrate an understanding of logic gates and Boolean logic
All
• To be-able to recognise a logic gate.
• To be-able to understand the three different logic gates (NOT, AND, OR).

Most
• To be-able to recognise the different logic gates and complete truth tables for them.
• To be-able to solve several gate problems.

Some
• To be-able to create a circuit using the different logic gates.
• To demonstrate a clear understanding of Boolean logic and Algebra.

Starter

#### Slide 4 -Slide

List all of the places you might find a circuit?

Main Activity

#### Slide 6 -Slide

Recap - What is a Logic Gate?
A logic gate is a device that acts as a building block for digital circuits. They perform basic logical functions that are fundamental to digital circuit.

#### Slide 7 -Slide

Recap - What is a 'Truth Table'?
This is a way of representing the inputs of the gates in a table using Boolean representation – 1’s & 0’s, or true & false. Each logic diagram has its own unique truth table.

#### Slide 8 -Slide

What are the different Logic Gates?

AND, OR, XOR, NOT, NAND, NOR and XNOR.

#### Slide 9 -Slide

The most common logic gates are:

AND Gate

NOT Gate

OR Gate

#### Slide 10 -Slide

AND Gate - Diagram and Truth Table
Output is true if: All inputs are true

#### Slide 11 -Slide

NOT Gate - Diagram and Truth Table
Output is true if:​ Input is false​
Output is false if:​ Input is true

#### Slide 12 -Slide

OR Gate-Diagram and Truth Table
Output is true if:​  At least one Inputs is true

#### Slide 14 -Slide

Logic.ly
Click on this link

Worksheet
Click on the link below and save it to your area.

#### Slide 15 -Slide

More than one input...
AND Gate

#### Slide 17 -Slide

More than one input
OR Gate

#### Slide 19 -Slide

Multiple Gates
Gates can be connected to other gates for more complex circuits​
Below we can see an AND gate along with a NOT gate.

#### Slide 21 -Slide

Multiple Gates
Below we can see an AND gate along with a OR gate.

#### Slide 23 -Slide

What we have learnt so far...
• Truth tables represent what a binary output will be based on binary inputs and the currently used logic gate​.

• AND gates will produce a binary value of 1 when all inputs are a binary value of 1​.

• OR gates will produce a binary value of 1 when at least 1 input is a binary value of 1​.

• NOT gates will produce the opposite value of the input.

#### Slide 24 -Slide

Boolean Algebra
What is 'Boolean Algebra'?

The text that describes the way the gates are connected.

Y = A AND NOT B

Y = NOT(A AND B)

#### Slide 27 -Slide

Y = (A AND B) OR C

#### Slide 28 -Slide

What would be the expression for this?

#### Slide 29 -Open question

In your small groups you must research the remainder of the gates. I want a definition and example.

XOR, NOR, XNOR, NAND

Be prepared to share with the class.

Plenary

OR
NOT
AND

#### Slide 32 -Drag question

What is the correct expression for the OR Gate
A
Y = A OR B
B
Y = A OR C
C
A OR B = Y
D
Y = A - B