Question:medium

In the following circuit, the value of Y is:

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When analyzing logic circuits, identify the gates and work from the input terminals forward to the output terminal, documenting the truth table values at each node.
Updated On: Jun 9, 2026
  • \( 0 \)
  • \( 1 \)
  • Varies between 0 and 1
  • \( 1/2 \)
Show Solution

The Correct Option is B

Solution and Explanation

Step 1: Recall the NAND rule.
A NAND gate gives output $0$ only when both its inputs are $1$. In every other case it gives $1$. Keep that single rule handy as we trace the circuit.
Step 2: Note the fixed input levels.
The circuit feeds in a constant $A = 1$ and a constant $B = 0$, and the $0$ first passes through a NOT gate (inverter).
Step 3: Invert the 0.
The NOT gate turns the $0$ into a $1$, so this branch now carries a logic $1$ onward to the next gates.
Step 4: Evaluate the first NAND stage.
Following the static logic levels through the lower NAND gate with its incoming signals, that gate settles to an output of $0$.
Step 5: Evaluate the gate that produces Y.
The gate giving $Y$ receives at least one $0$ from the previous stage. Since a NAND with a $0$ input must output $1$, the output stabilises at $Y = 1$.
Step 6: Conclude.
The feedback settles to a steady state with $Y = 1$, matching option 2.
\[ \boxed{1} \]
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