half adder (HA)
The half adder is a basic digital circuit that adds two binary numbers together. According to the dual arithmetic, the result can be two digits, for the decimal "2" a digital "10".
The half adder, which forms the basic circuit for the full adder, has two outputs like the latter, but only two inputs. It has no input to take over the carry of an upstream adder. This distinguishes it from the full adder.
The logic circuit of the half adder consists of three AND gates, two NOT gates and one OR gate. The gate arrangement has the two inputs "a" and "b" and the outputs "s" and "ü". The output "s" becomes "1" when one of the two inputs is "1". The output "ü" becomes "1" only if both inputs are "1".