Level 3: Perfect pair

Task

Build a logical AND gate.

AND outputs 1 only when BOTH inputs are 1.

Solution

NAND is an "inverted AND": it outputs 0 when both inputs are 1, and 1 in all other cases. If you feed NAND output into NOT, you flip the result back — getting pure AND!

Circuit: 1. Connect inputs A and B to the two NAND inputs. 2. Feed NAND output (Q) to NOT input. 3. Connect NOT output (Q) to Output.

Check: - A=0,B=0 → NAND=1 → NOT=0 ✓ - A=1,B=1 → NAND=0 → NOT=1 ✓