Question

What is a NAND gate? Give its logic symbol.

Answer 1

Hint: It is an electronic circuit. This electronic performs a logic function. We can express its function and characteristics by using the Boolean equation. It is not a version of AND gate. You will not find an abbreviation of NAND. It is not an acronym. Basically it means that it is a combination of AND and NOT then we made a shortcut as NAND.

Complete step-by-step answer:

INPUT 1	INPUT 2	OUTPUT
A	B	$Y=\overline{A.B}$
0	0	1
0	1	1
1	0	1
1	1	0

We all know what logic is. Here is little additional. We have to identify which logic gate we want to use according to our requirements. NAND gate is one of the types of logic gates. NAND is followed by NOT gate. It means that when NOT is connected before AND gate. NAND gate is derived from NOT and AND.
NAND gates have two inputs and one output. Logically it is a complement of AND. Any input may have low value or high value. When any of its inputs is LOW it produces HIGH output and it produces LOW output only when all of it is high, as you can see in above truth table.

Symbol of NAND:

Note: Here low value tends to 0 and high value tends to 1. Logic gate uses only two values which are 0 and 1. You can express and show output from input by using 0 and 1 as NAND’s input. These logic gates operate on discrete voltage levels.