Easiest CNT to build (Fan-out note included). Logic circuits, 28/101

A simple counter made of J-K flip-flops?
Yes sir, it may become very handy anytime you won’t need specialized counter packages, like when dealing with multiplexer selectors for instance!

In real situations, TTL normal series can be found together with LS, ALS and any CMOS flavor, all in the same diagram.

If you are cautious and don’t mix-up IC technologies, the fan-out shouldn’t be a problem. Use very bright LEDs as indicators. This way, you can keep their consumption to a couple of mA by increasing the limiting resistors value above 150Ω, up to 1KΩ.

In reality, TTL normal series ICs together with LS, ALS and any CMOS flavor, can all be present in the same project. Precautions should be taken, in order to prevent connecting conflicts. Otherwise, the poor project won't work.
And the fan-out is just one of these potential conflicts.

Here is the link to download the diagrams:
https://drive.google.com/drive/folder...

Useful links:
Binary to Decimal, quick and practical!    • Binary to Decimal, quick and practica...  
Synchronous vs Asynchronous Inputs.    • Synchronous vs Asynchronous Inputs. L...  
The anatomy of a Pulse.    • The anatomy of a Pulse. Logic Circuit...  
debounce Push Buttons!    • IC inverters at work: debounce Push B...  
Thanks for watching, and CU next time for decoders!