Question

The resultant gate and its Boolean expression in the given circuit is

• A. $\text{AND}, \overline{\text{A} + \text{B}}$
• B. $\text{NAND}, \text{A} + \text{B}$
• C. $\text{OR}, \text{A} + \text{B}$
• D. $\text{NOR}, \text{A} - \text{B}$

Hint:

A NOR output goes through an inverter, which cancels the bubble.

Answer 1

The Correct Option is C

Step 1: Reading the circuit:
The figure shows inputs A and B going into a gate with an OR shape and a small circle at its output (a NOR gate). Its output C then passes into a triangle with a circle (a NOT gate), giving output Y.

Step 2: Write the Boolean expressions:
\[ C = \overline{A + B}, \qquad Y = \overline{C} = \overline{\overline{A + B}} = A + B \]

Step 3: Truth table check:
A = 0, B = 0: C = 1, Y = 0. A = 0, B = 1: C = 0, Y = 1. A = 1, B = 0: C = 0, Y = 1. A = 1, B = 1: C = 0, Y = 1.
This is the OR truth table.

Step 4: Final Answer:
The combination is an OR gate with \(Y = A + B\), option (C).

Final Answer:
NOR followed by NOT gives an OR gate. \[ \boxed{\text{(C) }\text{OR},\ A+B} \]