Question

When the enable data input \( D = 1 \), select inputs \( S_1 = S_0 = 0 \) in the 1×4 Demultiplexer, then the outputs \( Y_0, Y_1, Y_2, Y_3 \) are

• A. \( Y_0 = 0, Y_1 = 0, Y_2 = 0, Y_3 = 1 \)
• B. \( Y_0 = 0, Y_1 = 1, Y_2 = 1, Y_3 = 0 \)
• C. \( Y_0 = 1, Y_1 = 0, Y_2 = 0, Y_3 = 0 \)
• D. \( Y_0 = 1, Y_1 = 0, Y_2 = 0, Y_3 = 1 \)

Hint:

A demux sends input to one of the outputs based on select lines.

Answer 1

The Correct Option is C

In a 1×4 demultiplexer, the enable data input \( D \) and select inputs \( S_1, S_0 \) determine which of the outputs \( Y_0, Y_1, Y_2, Y_3 \) will be set to 1. The rest of the outputs remain 0. For a demultiplexer:

• If \( D = 1 \), the demultiplexer is enabled.
• The select lines \( S_1, S_0 \) choose which output will be 1.

Given the inputs \( D = 1 \), \( S_1 = 0 \), and \( S_0 = 0 \), the logic is as follows:

• The select line configuration \( S_1S_0 = 00 \) directs the output to \( Y_0 \).
• Since \( D = 1 \), \( Y_0 \) will be 1.
• All other outputs \( Y_1, Y_2, \) and \( Y_3 \) will be 0.

Thus, the outputs for this configuration are:

\( Y_0 = 1, Y_1 = 0, Y_2 = 0, Y_3 = 0 \)