NAND gate-Truth Table

May 3 • General • 2917 Views • 2 Comments on NAND gate-Truth Table

NAND gate
Literally NAND gate is a circuit that is energized when any one of its inputs is not energized.
In digital electronics, a NAND gate (Negated AND or NOT AND) is a logic gate which produces an output that is false only if all its inputs are true. A LOW (0) output results only if both the inputs to the gate are HIGH (1); if one or both inputs are LOW (0), a HIGH (1) output results. It is made using transistors.
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.

The truth table of NAND gate is shown below
NAND gate truthtable

(The output is high when either of inputs A or B is The output high, or if neither is high. In other words, it is normally high, going low only if both A and B are high.
The NAND gate and the NOR gate can be said to be universal gates since combinations of them can be used to accomplish any of the basic operations and can thus produce an inverter an OR gate or an AND gate. The non-inverting gates do not have this versatility since they can’t produce an inverter.)

Some relevant points
-A NAND gate can be used to construct other logic gates such as AND, OR, NOR and others. This is why it is called a universal gate.
-The function NAND(a1, a2, …, an) is logically equivalent to NOT(a1 AND a2 AND … AND an).
-There are many advantages of nand gate
-It reduces the hardware (AND + NOT)
-It increases the speed of given ckt
-Since any gate can be constructed with the help of nand gate it is very useful in digital ckts.


1.Name a logic gate in which a signal passing through it is inhibited by sending a low into one of the inputs, and the output is HIGH.
Ans: NAND gate

2.How many NAND circuits are contained in a 7400 NAND IC?

3.Why NAND gate is called Universal gate?
Ans: NAND gates are one of the two basic logic gates (along with NOR gates) from which any other logic gates can be built. Due to this property, NAND and NOR gates are sometimes called “universal gates”.

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2 Responses to NAND gate-Truth Table

  1. suriya prakash says:

    This article explains about the NAND gate very clearly.

  2. Soubarna Biswas says:

    NAND gate is another important logic gate. This article clearly explains about it in details.

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