Question

Explain the operation of a NAND gate and its truth table.

Answer 1

A NAND gate (NOT-AND gate) is a fundamental digital logic gate that performs two operations simultaneously: it performs the logical NOT operation on the result of a logical AND operation. In other words, it produces the opposite of the output of an AND gate. The symbol for a NAND gate is often represented as a triangle with a small circle at its output.

A NAND gate has two or more input terminals and a single output terminal. Let's consider a NAND gate with two inputs, A and B:

If both input A and input B are at logic level 1 (HIGH), the output of the NAND gate will be logic level 0 (LOW).
For all other combinations of input values (A and B), the output of the NAND gate will be logic level 1 (HIGH).

Here's the truth table that summarizes the operation of a 2-input NAND gate:

A    B    Output
0    0    1
0    1    1
1    0    1
1    1    0

As you can see from the truth table, the output of the NAND gate is 1 (HIGH) for all input combinations except when both inputs are 1, in which case the output is 0 (LOW).

NAND gates are significant in digital logic design because they are universal gates, which means that you can use combinations of NAND gates to create any other type of logic gate (AND, OR, NOT, etc.). This property simplifies the design of complex digital circuits using a single type of gate.