PMOS

First Apple Computers

in
Comment from E-mail

I am thoroughly impressed by you creation of the first apple computers (and some other nifty electronic gadgets.) I have a nice little tech bench set up in my apartment, and spend a lot of time tinkering and inventing little projects, but nothing on the scale of a computer. I am aware that you gave away your schematics for the first Apple at the Stanford homebrew meetings, and was wondering if you still had a copy? I am very interested to see the components you used, and to gauge the possibility of building such a device on my own. I know that it will not bear the same accomplishment as actually designing the machine and then producing it 20 years ago, but I am very interested in the fundamental concepts of computers and would have a lot fun trying to make a computer. I was also wondering where you learned most of your electrical engineering. Books? school? any specific books or courses?

Woz

The schematics that I gave away were of the Apple I. It used some PMOS shift registers (2904 and 2919 I believe) to cycle the screen data, changing characters at the precisely right time. These chips, I'm sure, are unavailable today. The Apple ][ schematics were in our early manuals. You can probably find one of these somewhere. Although I started designing computers at an early age, ones I could never hope to build, I mainly built a lot of small projects. That's where I learned techniques. But today you can't design at the component and gate level as much if you're planning on a computer. It's pretty much all done in LSI chips. I learned my electronics from my father (an engineer), from early electronic kits (hard to find nowadays), from getting a ham radio license (you had to build your own tube based receiver and transmitter back then), from Popular Electronics magazine, from some rare computer journal articles, from Terman's book (a famous old one from the tube days, Terman taught at Stanford), from chip manuals with example circuits, and from computer manuals with logic diagrams of various parts and sometimes code examples.