The NAND gate is a circuit that outputs '0' when both inputs are '1', and '0' otherwise, ... full adder. is)'. A full adder can be realized by using the two half adders and the OR gate.

Looking at the NAND gate, ... As a quick example, let's look at a 1-bit full adder. This circuit takes three inputs (A, B, and Carry-In) and produces two outputs (Sum and Carry-Out).

He uses way too many relays. In the bad old days when we did have relay based computers we used grey code and not traditional binary. Also the relays had 3 stacks of up to 18 contacts.