The tech stuff you use every day, explained properly.
Simple explanations of everyday technology. Each topic is an interactive walkthrough: pick a step on the left, get the detail and the diagram on the right. Written for curious people and the IT folk who have to explain it to them.
Pick something to take apart
Each one follows the same shape: a journey down the left, the detail on the right. Start anywhere — they stand on their own.
How Wi-Fi actually works
From radio waves in the air to a web page on your screen — beacons, handshakes, DHCP, airtime and why the signal drops in the back bedroom.
What happens when you visit a URL
Press Enter and a few hundred milliseconds later there is a page. Inside that gap: DNS, a handshake, a certificate, a server on another continent and a browser building the thing in front of you.
How GPS actually works
Nothing in orbit knows where you are, and your phone never transmits. It works out its position by listening to clocks — and noticing exactly how late each one is running.
How 5G actually works
Your phone finds a network it has never seen, proves who it is to a company across the country, and is then told — two thousand times a second — exactly when it may speak.
How satellite television works
A picture goes 36,000 km straight up to a box that has hung over the equator for fifteen years, and comes back down across a whole continent — to a 45 cm mirror on your wall.
What happens when you turn on a computer
Thirty seconds of silence between the button and the desktop. It is the most carefully choreographed thing your machine ever does — and every layer hands over to the next.
How computers keep the right time
Every device you own is guessing what time it is, using a crystal worth a few pence. Everything from HTTPS to a global database depends on that guess being quietly corrected.
How fibre internet actually works
Light bounces down a thread of glass thinner than a hair, gets split thirty-two ways in a street cabinet, and your router has to log in before any of it counts as yours.
How a pocket calculator works
It answers instantly and has never been wrong — without a multiplication circuit, without understanding decimals, and with a solar panel that is barely doing anything.
How Bluetooth actually works
Two devices that have never met agree to talk, then change radio channel 1,600 times a second in a pattern only they know — in the noisiest band there is.
How USB actually works
Plug in something the computer has never seen and it works in a fraction of a second — after a formal interrogation in which the device is never allowed to speak first.
What happens when you pay by card
A chip performs a signature that can never be reused, a phone sends a number that is not your number, and the money does not actually move for two days.
How a hard drive actually works
A sensor flies two nanometres above a disc spinning at 120 times a second, finding one magnetic region among billions — and it must never once touch down.
How an SSD actually works
A bit is a handful of electrons trapped in glass. Nothing moves — but the drive can only erase in huge chunks, and everything awkward about it follows from that.
Technical References
Need the foundations rather than a journey? These plain-English references explain the protocols, signals and terminology from first principles.
Electromagnetic spectrum
Frequency, wavelength, radio bands, real-world uses and why spectrum is such an important shared resource.
DHCP protocol
DORA, IPv4 addresses, subnets, CIDR, leases, options, servers and relays.
DNS protocol
Resolvers, authoritative servers, delegation, caching, records and secure DNS.
HTTP protocol
Requests, methods, status codes, headers, cookies, caching and protocol versions.
TLS protocol
Encryption, certificates, trust, the TLS 1.3 handshake and what the padlock really means.
Multiplexing
FDM, TDM, WDM, CDMA, OFDM, OFDMA, spatial methods and MIMO.
Multimedia encoding
Common video and audio codecs, container formats, compression, quality and adaptive streaming.
Line codes
From NRZ and Manchester to block coding and the multi-level PAM used by modern links.
Lost in the acronyms?
Every acronym that appears anywhere in the guides — 141 of them — with what it stands for and what it actually means. Search it, or filter it down to one topic.