page_title: NAND gate
section_title: Implementations
hierarchical_section_title: NAND gate / Implementations
context_page_description: In digital electronics, a NAND gate 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 output results only if all the inputs to the gate are HIGH; if any input is LOW, a HIGH output results. A NAND gate is made using transistors and junction diodes. By De Morgan's theorem, a two-input NAND gate's logic may be expressed as AB=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. Digital systems employing certain logic circuits take advantage of NAND's functional completeness.
  The function NAND is logically equivalent to NOT.
  One way of expressing A NAND B is, where the symbol signifies AND and the bar signifies the negation of the expression under it: in essence, simply.
  NAND gates with two or more inputs are available as integrated circuits in transistor-transistor logic, CMOS, and other logic families.
caption: TTL NAND gate