Digital Electronics MCQ Questions & Answers | ECE

In Boolean algebra, the bar sign (-) indicates the NOT operation.

The NOT operation is a unary operation that inverts the value of a Boolean variable. If the variable is true, applying the NOT operation results in false, and vice versa.

OR operation and AND operation are indicated by + and • respectively in Boolean algebra, not by the bar sign.

Thus, Option C: NOT operation is the correct answer.

Understanding NAND Gates:
A NAND gate is a fundamental logic gate. It outputs a 0 (low) only when all its inputs are 1 (high). Otherwise, it outputs a 1 (high).

The Question: Connecting Inputs Together
Imagine you have a NAND gate with two inputs. Instead of giving them separate signals, we connect both inputs to the same input signal (let's call it 'A').

What Happens?
Now, both inputs of the NAND gate will always have the same value. If 'A' is 0, both inputs are 0. If 'A' is 1, both inputs are 1.

Let's Analyze the Output:
* If 'A' is 0 (both inputs are 0), the NAND gate outputs a 1.
* If 'A' is 1 (both inputs are 1), the NAND gate outputs a 0.

Comparing to Other Gates:
This output behavior is exactly the same as a NOT gate (inverter). A NOT gate simply inverts the input: 0 becomes 1, and 1 becomes 0.

Therefore, the correct answer is C: NOT gate