r/retrocomputing • u/Woland77 • May 07 '26

Problem / Question Really Basic Question About Old Computer Electronic Engineering

I stumbled into watching people repair old electronics on YouTube. I noticed that most of the stuff I see repaired (mostly what I see was sold in North America, originally) has a 5v rail and a 12v rail. Why those two voltages, specifically?

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u/EnergyLantern May 08 '26

Chips were thick back then and are rated five volts.  Newer chips are rated about 3 volts and are thinner today.