Multiplexer (MUX)

4-to-1 MUX — select one of 4 data inputs using 2 selector bits.

Data Inputs (I₀ – I3)
I0
I1
I2
I3
Selector
S0
S1
→
Output
1
Selector = 01 = 1 → route I1 = 1 to output
Block Diagram
MUX4-to-1I0=0I1=1I2=0I3=1S0=0S1=1Y=1
Selection Table
S0S1SelectedOutput
00I00
01I11
10I20
11I31
About the Multiplexer
A 4-to-1 multiplexer acts as a digital switch: it selects one of 4 data inputs and routes it to the single output based on the2-bit selector value. MUXes are used in data routing, bus arbitration, function generators, and can implement any Boolean function (a 2n-to-1 MUX can realize any n-variable function by connecting the inputs to 0 or 1 appropriately).