A half adder is a basic digital circuit used in electronics to perform the addition of two single binary digits, or bits. It has two inputs, typically labeled as A and B, and produces two outputs: the sum and the carry. The sum output represents the result of the addition, while the carry output indicates if there is an overflow, which occurs when both inputs are 1. Half adders are fundamental building blocks in more complex arithmetic circuits, such as full adders and adders used in computers. They are essential for binary addition, enabling the processing of binary numbers in digital systems.