Last week I revealed the sneaky physics behind the “joule thief,” an electrical circuit that lets you squeeze more energy out of seemingly dead batteries. The key, it turned out, was a clever pairing of a transformer and a transistor. But the transistor deserves its own headline, because it's maybe only the most important invention of the 20th century.
\n\nLife would be completely different without transistors. For starters, there would be no personal computers or cell phones, so no Amazon, no video games, no dating apps, no messaging, no streaming, no social media, no Apple Pay or Google Maps, and no AI (hmm). Cars contain billions of transistors. They're really everywhere. So what is a transistor?
\n\nThe best way to understand this pivotal technology is to follow the evolutionary trail, all the way back to the electric relays used in telegraphs in the 1800s.
\n\nTelegraph lines were basically long electrical circuits. And you probably never thought about it before, but they ran on batteries—primitive, low-voltage batteries that filled an entire closet at the telegraph station—because there was no electrical grid back then.
\n\nThe electric relay, invented in 1835, was a key component in these systems. Basically, it was a switch…
Original source: https://www.wired.com/