Which digital circuit performs addition on three binary numbers?

Which digital circuit performs addition on three binary numbers?

• A. Full-adder
• B. Half-adder
• C. Ripple Carry Adder
• D. Binary Adder

Answer: (A)

To add three binary values at a single bit position, you need a circuit that takes three inputs and produces a sum bit plus a carry-out. That’s what a full-adder provides: it adds two bits and a carry-in, giving a sum that is the XOR of the three inputs and a carry-out that goes high when at least two of the inputs are high. This single-stage, three-input capability is what lets full-adders be cascaded to handle wider, multi-bit addition (forming a ripple-carry adder when multiple stages are chained). A half-adder only handles two inputs and has no carry-in, so it can’t manage three inputs. A ripple-carry adder describes the series connection of full-adders for wider numbers, not the per-stage ability to add three inputs. A binary adder is a general term for circuits that add binary numbers, typically built from multiple stages, but it doesn’t specify the three-input-per-stage operation.

To add three binary values at a single bit position, you need a circuit that takes three inputs and produces a sum bit plus a carry-out. That’s what a full-adder provides: it adds two bits and a carry-in, giving a sum that is the XOR of the three inputs and a carry-out that goes high when at least two of the inputs are high. This single-stage, three-input capability is what lets full-adders be cascaded to handle wider, multi-bit addition (forming a ripple-carry adder when multiple stages are chained). A half-adder only handles two inputs and has no carry-in, so it can’t manage three inputs. A ripple-carry adder describes the series connection of full-adders for wider numbers, not the per-stage ability to add three inputs. A binary adder is a general term for circuits that add binary numbers, typically built from multiple stages, but it doesn’t specify the three-input-per-stage operation.