Question

For a \(4\times1\) multiplexer, which of the following will be the combination of selection lines for getting \(I_2\) as output?

• A. \(S_1=1,\ S_0=1\)
• B. \(S_1=1,\ S_0=0\)
• C. \(S_1=0,\ S_0=1\)
• D. \(S_1=0,\ S_0=0\)

Hint:

In a \(4\times1\) MUX, the binary value of selection lines selects the input number.

Answer 1

The Correct Option is B

Concept:
A \(4\times1\) multiplexer has four input lines: \[ I_0,\ I_1,\ I_2,\ I_3 \] and two selection lines: \[ S_1,\ S_0 \]

Step 1: Write selection table. \[ S_1S_0=00 \Rightarrow I_0 \] \[ S_1S_0=01 \Rightarrow I_1 \] \[ S_1S_0=10 \Rightarrow I_2 \] \[ S_1S_0=11 \Rightarrow I_3 \]

Step 2: Required output is \(I_2\).
For \(I_2\), selection input must be: \[ 10 \] So, \[ S_1=1,\quad S_0=0 \] \[ \therefore \text{Correct Answer is (B)} \]