Question 1

What is a NAND truth table?

Accepted Answer

A NAND truth table shows all input/output combinations for the NAND gate. NAND outputs FALSE (0) only when ALL inputs are TRUE (1). For two inputs: A=0, B=0 → 1; A=0, B=1 → 1; A=1, B=0 → 1; A=1, B=1 → 0. It's the inverse of AND.

Question 2

Why is NAND called a universal gate?

Accepted Answer

NAND is universal because you can build ANY other logic gate (AND, OR, NOT, XOR, NOR) using only NAND gates. This makes it extremely important in digital circuit manufacturing – entire processors can be built using just NAND gates.

Question 3

How do you build other gates from NAND?

Accepted Answer

NOT: Connect both NAND inputs together. AND: NAND followed by NOT (another NAND as inverter). OR: NOT each input, then NAND them together. This universality makes NAND gates the building blocks of modern computers.

Question 4

What is the Boolean expression for NAND?

Accepted Answer

The NAND expression is (A·B)' or NOT(A AND B), written as A NAND B. It can also be expressed as A' + B' using De Morgan's theorem. The output is the complement of the AND operation.

NAND Truth Table – The Universal Gate Calculator

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