You are given two circuit as shown in Fig.and . Which consists of NAND gates. Identify the logic operation carried out by the two circuits.

Explanation

From fig(a). The output of NAND gate is connected to NOT gate (obtained from NAND gate ) Let `y^(1)` be the output of NAND gate and the final output of the combination of two gates is Y. The output of a NAND gate is O only when both the inputs are zero, while in NOT gate, the input gets inverted. Truth table for the arrangement

It is the truth tables of AND gate. Therefore the given circuit acts as AND gate.
(b) The output of two NOT gates are connected to NAND gate Let `Y_(1)andY_(2)` be the outputs of the two NOT gates and the final output of the combination of three gates be Y. In a NOT gate. the input gets inverted, while the output of a NAND gate is .O. only when both the inputs are zero. Truth table for given arrangement.