The new biography Steve Jobs contains a remarkable claim about the power supply of the Apple II and its designer Rod Holt: [1] Instead of a conventional linear power supply, Holt built one like those used in oscilloscopes. It switched the power on and off not sixty times per second, but thousands of times; this allowed it to store the power for far less time, and thus throw off less heat. "That switching power supply was as revolutionary as the Apple II logic board was," Jobs later said. "Rod doesn't get a lot of credit for this in the history books but he should. Every computer now uses switching power supplies, and they all rip off Rod Holt's design." 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.…