Question

The given circuit diagram shows the implementation of a logic function using NAND gates.

Answer 1

The circuit represents an OR gate.

Answer 2

The circuit consists of three NAND gates. The first two NAND gates have their inputs tied together, making them function as NOT gates, producing $\overline{A}$ and $\overline{B}$ respectively. These inverted outputs are then fed into a third NAND gate. The output of this third NAND gate is $\overline{\overline{A} \cdot \overline{B}}$. By applying De Morgan's theorem ($\overline{X \cdot Y} = \overline{X} + \overline{Y}$) and the double negation rule ($\overline{\overline{X}} = X$), the expression simplifies to $A+B$, which is the Boolean expression for an OR gate.