Question

Identify the logic operation performed by the given circuit.

• A. NAND
• B. NOR
• C. OR
• D. AND

Answer 1

The Correct Option is C

The given circuit consists of two NOT gates and one OR gate. To identify the logic operation, let's analyze the circuit step-by-step:

Each input (A and B) passes through a NOT gate. The function of a NOT gate is to invert the input signal.

• If A = 0, then after NOT, the output is 1. 
• If B = 0, then after NOT, the output is 1.
• If A = 1, then after NOT, the output is 0.
• If B = 1, then after NOT, the output is 0.

The outputs of the NOT gates are then fed into an OR gate. The OR gate outputs 1 if at least one of its inputs is 1.

• For (A', B') = (0, 0), the OR gate output is 0.
• For (A', B') = (0, 1) or (1, 0) or (1, 1), the OR gate output is 1.

Combining these, we realize that the entire circuit performs an OR operation on the outputs of the NOT gates. Since the NOT gates invert A and B before passing to the OR gate, the final operation resembles an OR operation.

Therefore, the correct answer is OR.

Answer 2

The circuit simplifies to:

\[ Y = \overline{\overline{A} \cdot \overline{B}} = \overline{\overline{A}} + \overline{\overline{B}} = A + B \]

(De-Morgan’s law)