Logic Lab
Universal Gates
Build every other gate from only NAND gates or only NOR gates, and check each build against the real gate.
Build gates from NAND only
Make a
A B Output 0
Where one signal enters both pins of a gate, the inputs are tied together and the gate acts as a NOT.
Netlist: 2 NAND gates
1
n1NAND(A, B)0
YNAND(n1)inputs tied: acts as NOT| A | B | AND | NAND build | match |
|---|---|---|---|---|
| 0 | 0 | 0 | 0 | ✓ |
| 0 | 1 | 0 | 0 | ✓ |
| 1 | 0 | 0 | 0 | ✓ |
| 1 | 1 | 1 | 1 | ✓ |
NAND and NOR are universal: either one alone can build every other gate. Tying both inputs of a NAND gate together makes a NOT. AND is a NAND followed by that NOT; OR is NAND of the two inverted inputs (De Morgan). Every row of the build matches the real gate.