[Phillip] wanted to play with the C preprocessor. He decided to do that by creating a 4 bit full adder. We know this is pretty useless in everyday life, but it was a great learning experience. The … ...

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. It’s a rather unorthodox use of the part, d… ...

The approach for the design is based on XOR/XNOR & Transmission gate for single bit as hybrid design. By using this approach full adder is being designed using 12 transistors.

This paper focuses on the implementation and simulation of 4-bit, 8-bit and 16-bit carry look-ahead adder based on Verilog code and compared for their performance in Xilinx.