Question

You are given two circuits as shown in Fig. 14.46, which consist of NAND gates. Identify the logic operation carried out by the two circuits.

Answer 1

In both the given circuits, A and B are the inputs and Y is the output.

Hence, the output of the combination of the two NAND gates is given as:

Hence, this circuit functions as an AND gate.
(b)A Bar  is the output of the upper left of the NAND gate and B Bar  is the output of the lower half of the NAND gate, as shown in the following figure.

Hence, this circuit functions as an OR gate.