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 ...

although 1- and 2-bit devices were also made. Connected to a control unit, the ALU slices were strung together to make larger processors (8-bit, 16-bit, etc.). They included inputs and outputs for ...