Interpret the circuit

This standard question from electronic devices usually shows a diode-transistor style logic arrangement where the output becomes HIGH only when all inputs are HIGH.

That behavior corresponds to the truth table of an AND gate.

Recall the logic conditions

• AND gate: output $Y=1$ only if all inputs are $1$
• OR gate: output $Y=1$ if at least one input is $1$
• NAND gate: output is the inverse of AND
• NOR gate: output is the inverse of OR

Match the circuit behavior

For the given digital circuit, conduction/output conditions imply:

• if any input is LOW, the final output does not become HIGH
• only when all inputs are HIGH, the output is HIGH

Hence, $Y = A \cdot B$ which is the AND operation.

Check options

• A: NOR $\rightarrow$ incorrect
• B: AND $\rightarrow$ correct
• C: NAND $\rightarrow$ incorrect
• D: OR $\rightarrow$ incorrect

Final answer

The logic operation is equivalent to AND gate.