How Do Computers Work? | Explained in Under 10 Minutes

What this episode covers

Lewis opens with the device you're probably listening on right now: billions of tiny switches flipping on and off, millions of times per second, somehow producing music, spreadsheets, and this conversation. The switch is a transistor — three terminals, one signal, current either flows or it doesn't. On or off. That's the entire foundation. And because a switch is either on or off, binary isn't arbitrary — it's dictated by physics.Neev traces the idea backwards: the Antikythera mechanism, a Greek bronze computing device from 100 BCE that could predict lunar eclipses. Babbage's Difference Engine in the 1830s. ENIAC in 1945, filling 1,800 square feet and weighing thirty tons, capable of five thousand additions per second. Emma's phone does billions. A modern CPU has roughly fifty billion transistors etched into silicon — the smallest features around two nanometres across, a human hair seventy-five thousand nanometres wide.Emma explains the fetch-decode-execute cycle, RAM vs storage, and why the operating system matters. Neev brings in the GPU — originally built for video games, now the engine of all modern AI, because ten thousand moderately clever processors solving simple tasks in parallel beats one genius working sequentially. Lewis closes on the cost most people don't see: global data centres consume electricity comparable to mid-sized countries; training a single large AI model generates as much carbon as five cars over their lifetimes. The miracle and the cost — inseparable.If you enjoyed this episode, please subscribe — and send your topic suggestions to [email protected]. We read every one.

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