This is the groundwork for the half adder . The next step is the operational logic, which of course falls ... The standard adder uses OR for the last 'gate' - this can safely be changed to XOR ...

An elementary electronic circuit in the arithmetic logic unit (ALU) of the CPU that adds one bit to another. The output of the half-adder is a result of 0 or 1 and a carry of 0 or 1. Additional ...

Logic gates have one or two 0 or 1 inputs but only one 0 or 1 output as in the following examples. Transistors make up gates, gates make up circuits, and circuits make up electronic systems.