Being familiar with the hijinks that Steve Wozniak pulled with the switched mode power supply in the Apple II (1977), I was curious about how the author solved for this piece:<p>> It also needed three supply voltages; +5v, +12v, and -5v. That made it tough to power it from a single-voltage power supply or battery.<p>According to <a href="https://www.allaboutcircuits.com/news/mc34063-the-switching-regulator-that-defined-cheap-power/" rel="nofollow">https://www.allaboutcircuits.com/news/mc34063-the-switching-...</a>, the solution - the MC34063 - isn't _exactly_ a design that's contemporary with the Altair or other 1970s micros, but was introduced in the early 1980s. That would put it closer in age to the Commodore 64 which, in spite of its much smaller size, still indeed does not fit in an Altoids tin.<p>Very cool project nonetheless!
Woz only did the digital designs. The Apple II power supply was designed by Rod Holt.<p><a href="https://www.righto.com/2012/02/apple-didnt-revolutionize-power.html" rel="nofollow">https://www.righto.com/2012/02/apple-didnt-revolutionize-pow...</a>
I had the same question! When you open an Altair or IMSAI the giant, heavy linear power supply really stands out to modern eyes.