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Ken Shirriff's blog: Apple didn't revolutionize power supplies; new transistors did

Stashed in: Steve Jobs, Apple, History of Tech!

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I found it amazing to think that computers now use power supplies based on the Apple II's design, so I did some investigation. It turns out that Apple's power supply was not revolutionary, either in the concept of using a switching power supply for computers or in the specific design of the power supply. Modern computer power supplies are totally different and do not rip off anything from Rod Holt's design. It turns out that Steve Jobs was making his customary claim that everyone is stealing Apple's revolutionary technology, entirely contrary to the facts.

The history of switching power supplies turns out to be pretty interesting. While most people view the power supply as a boring metal box, there's actually a lot of technological development behind it. There was, in fact, a revolution in power supplies in the late 1960s through the mid 1970s as switching power supplies took over from simple but inefficient linear power supplies, but this was a few years before the Apple II came out in 1977. The credit for this revolution should go to advances in semiconductor technology, specifically improvements in switching transistors, and then innovative ICs to control switching power supplies.[2]

Steve Jobs never let facts get in the way of a good story.

Still, even without stealing from Apple, this is a good story.

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