# Transistor The transistor is a tiny electronic switch with no moving parts: a small voltage on one terminal controls whether current flows between two others. That is all it does — turn a current on or off, or amplify it — but it is the single most-manufactured device in human history and the building block of all digital computing. A "1" or "0" in a computer is ultimately a transistor switched on or off. Invented at Bell Labs in 1947, transistors were once individual components the size of a fingernail. Today they are etched onto a [[Semiconductor]] chip by the billions; a modern phone processor packs on the order of ten-to-twenty billion of them onto a fingernail-sized die. The decades-long trend of cramming more transistors into the same space — roughly doubling every two years — is called Moore's Law, and its gradual slowing is one reason chipmaking has gotten so expensive and so concentrated. ## Why it matters here The transistor itself carries no politics — it is pure infrastructure. It earns a place in this lexicon because it is the literal atom of everything else the vault tracks in tech: the count and density of transistors is what defines an "advanced" chip, and "advanced chips" are exactly what [[Chip Export Controls]] try to keep out of Chinese hands. Understanding that a chip is just a vast city of switches demystifies why fabrication is so hard and why the [[Semiconductor]] supply chain became a geopolitical chokepoint. ## See Also - [[Semiconductor]] — the material the transistor is made from - [[System on a Chip]] — billions of transistors organized into a whole computer - [[Central Processing Unit]] — the logic engine transistors build