Multiplexer (MUX) Calculator

What is a Multiplexer (MUX)?

A multiplexer is a digital circuit that selects one of several input signals and forwards it to a single output line. It acts as a digital switch, controlled by select lines that determine which input is connected to the output.

How to Use This Calculator

1. Select MUX type - Choose 2:1, 4:1, or 8:1 multiplexer
2. Set input values - Configure data inputs and select lines
3. Click "Calculate" to see the selected output
4. View results including truth table and Boolean expression
5. Copy or export the analysis for your projects

Types of Multiplexers

2:1 Multiplexer

Has 2 data inputs (I0, I1) and 1 select line (S0). The select line determines which input is routed to the output.

• Expression: Y = ¬S0·I0 + S0·I1
• When S0 = 0: Output = I0
• When S0 = 1: Output = I1

4:1 Multiplexer

Has 4 data inputs (I0-I3) and 2 select lines (S0, S1). The combination of select lines determines which input is selected.

• S1=0, S0=0: Output = I0
• S1=0, S0=1: Output = I1
• S1=1, S0=0: Output = I2
• S1=1, S0=1: Output = I3

8:1 Multiplexer

Has 8 data inputs (I0-I7) and 3 select lines (S0, S1, S2). Provides selection among 8 different input sources.

Applications and Uses

Data Routing

• CPU data path selection
• Memory address multiplexing
• Bus switching in computer systems
• Input/output port selection

Digital Systems

• Function generators
• Data acquisition systems
• Digital communication
• Parallel-to-serial conversion

Examples & Worked Problems

Example 1: 2:1 MUX

Problem: I0=1, I1=0, S0=0. What is the output?

Solution:

• Since S0=0, the MUX selects I0
• Output = I0 = 1

Example 2: 4:1 MUX

Problem: I0=0, I1=1, I2=0, I3=1, S1=1, S0=0. Find output.

Solution:

• Select lines: S1=1, S0=0 → selects I2
• Output = I2 = 0

Design Considerations

Propagation Delay

• Data-to-output delay
• Select-to-output delay
• Enable-to-output delay

Fan-out and Loading

• Output driving capability
• Input loading effects
• Power consumption

Related Tools