Introduction, digital abstraction and binary.
Understand digital circuits with illustrated explanations, worked examples, past-paper discussions and revision questions.
Study sections
Follow the order or choose a sectionWhat Is a Computer System?
Your phone, a smart watch, a washing machine, a drone, a self-driving car, even a smart speaker. They look completely different. But in…
02From Transistors to Chips, and Moore's Law
A modern phone chip has billions of transistors. That’s more tiny switches than there are people on Earth, packed into something smalle…
03Representing Information with Voltage
Long ago, people stored information by carving on stone. Your body stores information in DNA. A computer has no stone and no DNA. It ha…
04The Digital Abstraction — Why Computers Use 0 and 1
Play “telephone”: whisper a sentence to a friend, who whispers it to the next, and so on down a line of ten people. By the end, the sen…
05Binary Numbers and Place Value
One light bulb can show only two things: off or on. Two bulbs can show four patterns. Three bulbs, eight. With enough bulbs you can sho…
06Other Bases — Octal, Hexadecimal and Any Base
Binary numbers get long very fast: 1011011011101110 is hard to read and easy to copy wrong. So engineers use a short form called hexade…
07From Logic to Circuits — Boole and Shannon
“If it’s raining and I have an umbrella, I’ll go out.” “If it’s Sunday or a holiday, there’s no school.” You use logic every day. About…
08How to Solve Week 1 Exam Questions
Every Week 1 question in the past papers is on this page, with the exact paper it came from. For each type you first learn the method f…