At an earlier post I’ve said that I didn’t have 7400ICs in my drawer.
Surprisingly, the local store was saying 74HC00 out of stock. Hence I decided to make my own 7400 IC.
7400 is a quad two input NAND gate.
Any digital circuit can be made with universal gates like NAND or NOR, even some pretty analog circuits can be made using these as the competition entries show.
Via the forum.