Lab 3 of 15 · rank 02
Y = A XOR B. The half-adder’s sum bit.
Learn first
Turn a light on when exactly one of two switches is on — that's XOR. It's the gate that adds two bits without the carry, so it's the heart of every adder.
You can build it from four NANDs: one NAND shared in the middle, one NAND per input that mixes the input with that middle signal, and a final NAND that joins the two. It looks like a diamond.
NAND #1 takes A and B. NAND #2 takes A and the output of #1. NAND #3 takes B and the output of #1. NAND #4 takes the outputs of #2 and #3, and its output is Y. Not sure? Press Examples in the Studio later — but try it here first.
Turn logic into a permanent, verifiable part.
Classic 4-NAND XOR, or the XOR cell.
Par is 4 NAND. Using more still passes here. To etch it as a verified die that mines, keep it within 8 NAND-equivalent (a LATCH counts 2): the verifier refuses bigger designs, so padding can't buy mining weight.
Turn this circuit into a verified die you own. It burns 0 NAND. Get materials at the Foundry.