This 2-bit adder was a lot of work to build. It uses a total of thirty-six 555 timers and it does have the option of adding or subtracting numbers.

The way they’re illustrating how a full adder works is the killer feature here: they’re using EL wire for all of the wires connecting the gates.

Power and delay optimization is a very crucial issue in low voltage applications. In this paper, the authors present a design of Full Adder circuit using AVL techniques for low power operation ...

In the latest technology developed by MicroAlgo, they have successfully implemented the FULL adder operation using CPU registers based on quantum gate computers.