A two-input logic gate is giving high output only when both the inputs are high. For all other input conditions, the output is low. Select the correct logic gate.
AND gate
The question describes a two-input logic gate characterized by a specific input-output relationship: the output is high ($1$) only when both inputs are high ($1$). For all other input combinations, the output is low ($0$).
Analyzing Logic Gate Behavior
This unique behavior defines the function of the logic gate. We need to identify which standard logic gate operates this way.
Let the two inputs be denoted by A and B, and the output by Y. The defining condition can be stated as:
- Y = $1$ if and only if A = $1$ AND B = $1$.
- Y = $0$ otherwise.
Truth Table Representation
The behavior can be clearly illustrated using a truth table. Here, '$0$' represents a low logic level and '$1$' represents a high logic level.
| Input A | Input B | Output Y |
| $0$ | $0$ | $0$ |
| $0$ | $1$ | $0$ |
| $1$ | $0$ | $0$ |
| $1$ | $1$ | $1$ |
Identifying the Specific Logic Gate
Let's compare this truth table to the standard two-input logic gates:
- AND Gate: Its output is $1$ only when both inputs are $1$. This perfectly matches the truth table derived from the question's description. The Boolean expression is $Y = A \cdot B$.
- NAND Gate: This is the negation of the AND gate ($Y = \overline{A \cdot B}$). Its output is $0$ only when both inputs are $1$.
- OR Gate: Its output is $1$ if at least one input is $1$ ($Y = A + B$).
- NOR Gate: This is the negation of the OR gate ($Y = \overline{A + B}$). Its output is $0$ if at least one input is $1$.
Therefore, the logic gate described in the question, which outputs high only when both inputs are high, is the AND gate.
Important Questions from Logic Gates
The output is high only if one of the input is high. The above statement represents _____
The number of gate inputs, required to realize expression ABC + AB̅CD + EF̅ + AD is
Which of the following is logically equivalent?
A. ¬p → (q → r) and q → (p ∨ r)
B. (p → q) → r and p → (q → r)
C. (p → q) → (r → s) and (p → r) → (q → s)
Choose the correct answer from the options given below :
Consider the expression Y = P ⨁ Q ⨁ R where P, Q, R are the input variables and Y is the output variable. Y will be logic 0 if
(A) an odd number of input variables are 1
(B) an even number of input variables are 1
(C) an odd number of inputs variables are 0
(D) an even number of input variable are 0
(E) an odd number of input variable between 0 and 1
Choose the correct answer from the options given below:
Match List I with List II
List – I
List – II
Logic gate
Truth table
A.
Negative OR
I.
A
B
F
0
0
1
0
1
0
1
0
0
1
1
0
B.
Exclusive NOR
II.
A
B
F
0
0
1
0
1
1
1
0
1
1
1
0
C.
Exclusive OR
III.
A
B
F
0
0
1
0
1
0
1
0
0
1
1
1
D.
Negative AND
IV.
A
B
F
0
0
0
0
1
1
1
0
1
1
1
0
Choose the correct answer from the options given below:
