Lesson 4 - Binary Logic

Lesson 4 - Binary Logic

Task

COMBINING LOGIC GATES

• Complete questions 6-8 on worksheet 1

• advanced logic - complete questions 9-12 on worksheet 2

• Super advanced task - see me!

we CAN COMBINE LOGIC GATES TO MAKE MORE COMPLEX CIRCUITS

Plenary

Draw a diagram of the three Logic Gates that you have learned about today - without looking at your worksheets!

loGIC GATES

Logic gATES

not (a or b)

• so the previous circuit is a combination of an and gate plus a not gate

• We first process the two inputs, and then use the output to feed into the next gate.

• george boole developed a way of writing this down as not (a and b)

• he called this boolean algebra!

What would the truth table look like for this?

Binary Logic

Logic Gates

The circuit to store a single bit of data is made from a transistor and a capacitor.

A capacitor can store electrons, and it can be in one of two states:

‘charged’, full of electrons;

‘discharged’, empty.

A transistor is a switch that allows the control circuit to:

check if there is a charge stored in the capacitor or not;

change the state of the capacitor.

Logic gates

thE or GATE

There are three main lOGIC gates

Notice the difference in the truth tables?

The not Gate

Why does the inverter only have two possible outputs?

To work out the number of possible combinations in a truth table you must work out:

2 to the power of n

where N is the number of inputs

Then count in binary!

outputs high if one or more inputs are high

• The digital computer uses an arrangement of tiny electronic switches (transistors) called logic gates connected together.

• These logic gates are used to manipulate the signals within the processor (in other words, change whether the output is true or false! )

• The logic gates are all connected to allow the processor to receive and pass on electronic signals

Binary Logic

TASK

SO BINARY LOGIC IS USING and, or AND NOT'S TO MANIPULATE THE OUTPUTS OF GIVEN INPUTS....

cOMPLETE QUESTIONS 1-5 ON WORKSHEET 1

John Von Neumann architecture (1945)

• Both data and programs are stored in the same place, in the computer’s memory (Where was colossus' program stored?)

• Both data and instructions are stored in binary (what is binary?)

The AND GATE

hint - thINK ABOUT QUESTIONS 4 AND 5 LOGICALLY....can you remember how to count in binary?

oNLY OUTPUTS HIGH IF all of the INPUTS ARE HIGH

Learning Mat

What is binary Logic?

Learning Objectives

Binary logic, also referred to as Boolean logic, is a set of rules for dealing with propositions that must be either true or false.

• any part can be completed by any person at any time.

• it will need to be fully complete before you are allowed to leave

• If you get stuck during the lesson see if your learning mat has the answer!

• To be able to explain what Binary Logic is

• To understand what is meant by the terms AND, OR and NOT

• To understand what a logic gate is and use it to produce Truth Tables

• To be able to combine two logic gates and produce Truth Tables

Starter

What is the act that governs the protection of data?

What is the purpose of the computer misuse act?

What are the basic functions of an operating system?