In digital electronics, a NAND gate ( NOT-AND ) is a logic gate which
produces an output which is false only if all its inputs are true; thus its
output is complement to that of an AND gate. A LOW (0) output results only if
all the inputs to the gate are HIGH (1); if any input is LOW (0), a HIGH (1)
output results. A NAND gate is made using transistors and junction diodes. By
De Morgan's laws, a two-input NAND gate's logic may be expressed as A • B=A+B,
making a NAND gate equivalent to inverters followed by an OR gate.
The NAND gate is significant because any boolean function can be implemented
by using a combination of NAND gates. This property is called functional
completeness. It shares this property with the NOR gate.