Is This The Most Common Chip Nobody Has Heard Of?

There's a good chance one is plugged into your wall right now. The TL431, a three legged chip Texas Instruments announced in 1977, sits inside most phone chargers, laptop power bricks and PC power supplies. A typical PC power supply often has three. Almost nobody knows its name. This is the story of the zener diodes that drifted with the temperature, the bandgap trick from Fairchild and Bob Widlar, the switching power supply revolution, the light bridge between the dangerous and safe sides of your charger, the Apple II, the cheap knockoffs that leave it out, and the EU charger law of 2026. Watch the 2N3055 story, the transistor that ran the old linear power supplies: [https://youtu.be/ojcTmYA_7-k?si=Y8I0DH8lpcEcCYpE Watch the Bob Widlar story, the engineer behind the first bandgap regulators: https://youtu.be/1Hsy1xwxNDE Have you ever opened a dead charger or PC power supply and found a 431? Tell me in the comments. And if I got a date, a number or a name wrong, tell me there too. I read every comment and I pin corrections. Parts That Changed History tells the stories behind the chips, machines and parts that shaped the modern world, and the people who built them. Subscribe for a new story every day. #TL431 #TexasInstruments #PowerSupply #Electronics #ElectronicsHistory #Chip #Semiconductor #PhoneCharger #USBC #TechHistory #Engineering #Documentary #PartsThatChangedHistory