Apollo-Era Digital Logic

[wholder]

I've been experimenting with some of the very first Fairchild, "micrologic" series, integrated circuits.  These are the same type of ICs used to build some versions of the Apollo Guidance Computer (AGC.)  I was able to located a few uL923 parts, which are documented as JK Flip Flips, and get them working as a ripple counter.  The AGC is said to have been built entirely using dual, triple NOR gates in flat packs, but I have been unable to locate similar parts on the surplus market.  So, I settled for using the uL923 which, while in the same family as the ICs used in the AGC, are packaged in expoy-based, TO-99 configuration.  If you're interested, I've written a short article with a demo video which you can see here:

  https://sites.google.com/site/wayneholder/apollo-era-digital-logic

These early fairchild RTL ICs were used as the basis of quite a few projects in the old American hobbyist magazine "Popular Electronics".  For example, Don Lancaster's "IC-67 Metal Detector" on page 41 of the the January, 1967 Issue (http://www.americanradiohistory.com/Archive-Poptronics/60s/67/Pop-1967-01.pdf) was based on the uL914, which is a dual, two input NOR gate that's very similar to the parts used to build the AGC.  Lancaster even managed to use these "digital" ICs as analog devices in the receiver portion of the metal detector.

Wayne

[coppice]

Oh, that takes me back. I learned digital design by experimenting with Motorola MC7xx series RTL devices. I think the MC7xx series was the first time a group of ICs really formed a coherent family. Motorola had a separate MC8xx series of DTL devices. The Fairchild uL9xx devices were a mixture of RTL and DTL (maybe even TTL), which were not mutually compatible. There was no clear sense of devices families with these. Although these devices were available in TO99 packages, for high reliability applications, most were supplied in DIL packages looking exactly like the ones you can buy today.

[wholder]

I remember the MC7xx series well, too.  I believe it was used in a lot of PopTronics projects, as well.

Wayne

Oh, that takes me back. I learned digital design by experimenting with Motorola MC7xx series RTL devices. I think the MC7xx series was the first time a group of ICs really formed a coherent family. Motorola had a separate MC8xx series of DTL devices. The Fairchild uL9xx devices were a mixture of RTL and DTL (maybe even TTL), which were not mutually compatible. There was no clear sense of devices families with these. Although these devices were available in TO99 packages, for high reliability applications, most were supplied in DIL packages looking exactly like the ones you can buy today.