Question

In the circuit shown below, Y is a 2-bit (Y\(_1\)Y\(_0\)) output of the combinational logic. What is the maximum value of Y for any given digital inputs, A\(_1\)A\(_0\) and B\(_1\)B\(_0\)? 

• A. 01
• B. 10
• C. 00
• D. 11

Hint:

In NAND gates, the output is 1 when at least one input is 0, which helps maximize the output value.

Answer 1

The Correct Option is A

The given circuit consists of NAND gates. The first NAND gate takes inputs A\(_1\) and A\(_0\), and the second NAND gate takes inputs B\(_1\) and B\(_0\). The outputs of these gates are then fed into another set of NAND gates to generate the 2-bit output Y = (Y\(_1\), Y\(_0\)).
- The maximum value of Y occurs when both Y\(_1\) and Y\(_0\) are at their highest possible values, i.e., when the outputs of the NAND gates are both 1. - Since the output of a NAND gate is high when at least one of the inputs is 0, the maximum value for Y = (Y\(_1\), Y\(_0\)) is achieved when all inputs are at their lowest possible values (0). Thus, for inputs A\(_1\) = 0, A\(_0\) = 0, B\(_1\) = 0, and B\(_0\) = 0, the output Y = 01. Final Answer: 01