Assume a 8x1 multiplexer's data inputs have the following present values: i0=0, i1=0, i2=0, i3=1, i4=0, i5=0, i6=0, i7=0. What should be value of the select inputs s2, s1 and s0 for the value on the multiplexer's output d to be 1?

s2=

s1=

s0=

Answer: s₂ = 0 s₁ = 1 s₀ = 1

Explanation:

In brief, a multiplexer is a digital circuit (generally buit with combiantional logic), that selects one of the inputs to be present at the output, based on the combination of the values present in auxiliary inputs called select inputs.

As a rule, the number of inputs (m) and the number of select inputs (n) satisfy this condition: m = 2ⁿ

At any time, the input which order, be equal to the binary combination of the select inputs, will be present at the output.

In our case, being an 8x1 multiplexer, we will have 3 select inputs, denoted as s₂, s₁, s₀.

The only input which current value is "1", is i3, so, in order to send an "1"to the output, the binary combination at the select inputs must match the number of the input to be selected, i. e., 3.

So, s₂s₁s₀ must be read as 3 in binary; 011, so s₂=0 s₁=1 s₀ = 1.