I was thinking the other day while building a project that there are a lot of very useful IC's out there, and several I use often.
So I was wondering what everyone's favorite "chip" is to use? Let's leave out the obviously popular 555 timer and PICs.
I'll start: The 4017 Decade Counter.
The divide-by N feature is nice, but what I seem to use it for a lot is sequencing events. One example was to stagger the powering up of amplifiers & processors for a theatre to prevent a large current draw and to ensure things were kept "muted" until everything was on.
I've also used it in some larger digital circuits to perform certain tasks "in order". For example, making sure one portion of my circuit is reset before another and then enabling a clock or output after everything has been reset.
You are in a good position designing circuits with your favavorite chips.
The application of chips depends on the project I'm normally working at. So the chips used for that particular project are my favorite chips for the time being.
And that would be bad because why? There are enough misconceptions in every camp that reasonable discussion would be interesting. It does not have to be a pissing contest.
People without experiance in several camps would have little to offer. Other then... ask questions
When I was in school, I used to consider 741 opamp as the magical chip. I thought I would make several projects using it. almost always there turns out to be a better suited chip for any project even if based on the same basics as that of 741.
I would start with any chip that isn't a 555. I have never got on with it. The only circuit that I have worked on that used a 555 series (a 556 actually) was so badly designed that it would only work with one brand of 556, as it left the reset line high when turning the chip power off. Even before I came across that circuit, I didn't like the 555.
I much prefer a CD4093 for RC timing applications. It has a wide supply range, is about the same price as a 555, and can do astable or one-shot with just a resistor and a capacitor. Odd symmetries can be done with a diode, and combinations are easy because it is a logic gate. Even better, you get 4 in one IC.
As for neat circuits, I like the https://www.electro-tech-online.com/custompdfs/2008/12/74LVC1G80_8.pdf 74LVC1G80. Probably not much use for hobbyists as the largest package it is available in is less than 3mm square including pins, and the smallest is 1mm square. With no external components and by linking the NQ output to the D input, it divides the clock frequency by 2.
Another useful component is the self resetting fuse. For low voltage work they are great, and can make intermittent faults irrelevant or much easier to find.
Over the years I've used the CD4584 (aka. 74C14) Hex CMOS schmitt trigger inverter in lots of circuits. Everything from clock generators,pulse strechers,
pulse shorteners,one shots and timers,flip-flops,frequency doubler,switch debouncer and even an inverter. Im sure I've used more of this chip than any other.