What logic and digital chips to get ?

[KL27x]

About 30 years ago I desoldered several thousand of them, and nicely sorted them and put them in drawers.
They're still there.

I could say the same thing about microcontrollers, only change 30 years ago to 15. We get new flavors every now and then, and the old stuff just becomes obsolete. When you have 3, and that's all you have, you might find some cute use for them. You might think if you have a thousand, it will be even more useful. But if you have a project where you can use a thousand.... how do you know it will stop there? Then you are stuck having to port the project or continue using an obsolete part which might be overpriced or unreliable to source.

[lordvader88]

Think how many old projects that a hobbyist might make that still call for CMOS4000 chips, that's why I want a few more around

[james_s]

I could say the same thing about microcontrollers, only change 30 years ago to 15. We get new flavors every now and then, and the old stuff just becomes obsolete. When you have 3, and that's all you have, you might find some cute use for them. You might think if you have a thousand, it will be even more useful. But if you have a project where you can use a thousand.... how do you know it will stop there? Then you are stuck having to port the project or continue using an obsolete part which might be overpriced or unreliable to source.

I wouldn't recommend buying 1,000 of any part unless you're using large numbers of them, but having 10-20 microcontrollers around is handy. In a sense they do get obsolete but in many cases that doesn't really matter. Just last year I used a ATTINY13 I'd had in a drawer for years, it's an old part that is probably considered obsolete by most but it's just as useful as it ever was and for what I needed it was more than adequate. I've still got a pile of AT90S2313 AVRs I got close to 20 years ago when I was using them in projects, I still use one of those now and then too, if not for the fact that they require an external crystal or resonator I'd use them more often. I've built digital clocks, programmable controllers, traffic light and pedestrian crossing sign controllers and other various stuff. There's a lot you can still do with 2k of memory.

[ledtester]

I'd consider getting a couple of CD4007s to play around with. Over time I've seen a bunch of references to it in articles and projects. Just a few examples...

- http://www.learningelectronics.net/VA3AVR/tutorial/xtor/xtor10/xtor10.html
- https://wiki.analog.com/university/courses/electronics/electronics-lab-28
- Articles by Ray Marsten appearing in Nuts and Volts

The CD4007 gives you pairs of NMOS/PMOS transistors which are well-matched and that's important for cerain analog amplifier circuits.

[jfiresto]

... Just last year I used a ATTINY13 I'd had in a drawer for years, it's an old part that is probably considered obsolete by most but it's just as useful as it ever was and for what I needed it was more than adequate....

The ATiny13 (now ATtiny13A) is still quite useful. I went through the current AVR catalog a few months ago, and it and the ATtiny24 were the first, smallest parts that would address a design: the ATtiny24, directly, and the ATtiny13A, with a single gate, which the design needed, anyway, as a "coulomb buffer". All the rest had a least one grievous gotcha, each, that ruled them out. In this case, the ATiny13 improved on both its predecessors and successors.