Logic Gate: Output High When Inputs Same
The question asks to identify a 2-input digital logic gate. The key condition is that its output is HIGH only when both inputs are the same.
Analyzing Logic Gate Functions
We need to find the gate whose output is logic 1 when its inputs are identical (both 0 or both 1). Let's examine the options:
- EX OR Gate (XOR): Produces a HIGH output when inputs are *different*.
- EX NOR Gate (XNOR): Produces a HIGH output when inputs are the same. This matches the required condition.
- AND Gate: Produces a HIGH output only when *both* inputs are HIGH.
- NAND Gate: Produces a LOW output only when *both* inputs are HIGH (inverse of AND).
Based on the functionality, the EX NOR gate is the correct answer.
EXNOR Gate Characteristics
The EXNOR (Exclusive NOR) gate, also known as the XNOR gate, implements logical equality. Its output is HIGH if and only if the inputs are equal.
The Boolean expression is:
Output = $A \odot B$
Or
Output = $\overline{A \oplus B}$
Where $A$ and $B$ represent the two inputs.
EXNOR Gate Truth Table
| Input A | Input B | Output |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 1 |
The truth table confirms that the output is HIGH (1) exclusively when both inputs, A and B, are identical.
Similar Questions
In a logic circuit, two inputs A and B are applied to an AND gate, and the output of the AND gate is connected to the input of a NOT gate. If the inputs A and B are both at logic 0, what will be the output of the entire circuit?
In a logic circuit, three SPST (Single Pole Single Throw) switches are used to implement a logic gate. The switches are connected in series. What is the output of the circuit if all switches are closed?
_______ are universal logic gates.
- A three Input NOR gate gives high O/P when _____.
- The Output of NAND Gate is low in case ________
Important Questions from Logic Gates
Which logical gate is used to represent product of sum expression?
Which gate is represented by the following truth table?
Input
Output
A
B
C
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
0
Which logical gate is included in a binary adder circuit to enable binary addition and subtraction?
Which of the following represents the XNOR gate?
A Circuit that operates in such a way that its output is high only when all its inputs are high
