Teach Computing

Revision notes, activities, lesson plans, teaching ideas, and other resources for GCSE, A-Level, and IB Computer Science teachers and students.

What's New

Boolean logic worksheet pack

These three Boolean logic worksheets have exam style questions on logic sta...

Edexcel Computer Science (9-1)

by Ann Weidmann et al Amazon.com | Amazon.co.uk | Book Depository This bo...

Dijkstra's algorithm video

This video is probably the best explanation of Dijkstra's algorithm for IB ...

Input-Process-Output (IPO) Model

The Input-Process-Output model is a simple topic but some students sometime...


A comprehensive review of hexadecimal. The video covers not only how to u...

Subprograms, Local Variables & Structured Programming

Subprograms are known by several different names - methods, functions, proc...

Utility Software and Models

Some students find the difference between operating system software and ut...

Data Structures

This video explains different types of data structures - 1 dimensional ar...

Operating System (OS) - GCSE Computer Science

A detailed overview of operating systems, starting with the general tasks t...

3.3 Hardware

Click here for recommended Cambridge A-Level Computer Science textbooks.

3.3.1 Logic gates and circuit design


XOR and Half-Adder

This video starts by recapping the truth table for an exclusive-OR (XOR) gate, and then goes on to show how its properties can be used to help create a half-adder in conjunction with an AND gate. The video helps demystify the concept by building up the half-adder and explaining with examples why an additional gate is needed.

Updated: 2015-04-29

3.3.2 Boolean algebra

Boolean expression simplification

Logic Simplification Examples Using Boolean Rules

This is an excellent video which goes clearly through the individual steps of simplifying Boolean expressions. The video starts with a clear list of simplification rules and explains why they work. There are then two examples, complete with logic circuit diagrams, which are worked through line by line until they are fully simplified. This is probably the clearest explanation of Boolean simplification I have seen. (The video is a lot better than the screenshot makes it look!)

Updated: 2015-11-24

3.3.3 Karnaugh Maps

3.3.4 Flip-flops

3.3.5 RISC processors

3.3.6 Parallel processing

CERN Grid Computing

CERN Grid Computing system

This brief tour of the CERN computer grid gives a good overview of the computing system and the power available.

The second video features interviews with CERN employees who explain how the grid computing system works and how the data is transmitted to and processed by multiple tiers of computers spread across Europe.

Updated: 2015-05-27