Understanding Multiplexers

Hi everyone! Welcome back to Project 3 where we talk about combinational circuits. This is the last entry for this project and we will be discussing Multiplexers.

What are Multiplexers (also known as MUX)?

Multiplexers are electronic devices used in digital circuits to select and route one of several input signals to a single output line. They act as data selectors.

A multiplexer has multiple input lines and one output line. The number of inputs is usually a power of 2 (e.g., 2, 4, 8), and the output line carries the selected input signal.

It uses control signals (or selector lines) to choose which input to send to the output. For example, let’s take a look at a 4-to-1 multiplexer. It has 4 inputs, 2 selection lines (since 2^2=4), and 1 output.

Imagine a simple TV with 4 channels. You know that you can only watch one channel at a time and which channel you watch is based on what numbers you have pressed on the remote. To watch channel 1, you press 00 on your remote and to watch channel 2, you press 01, for channel 3, you press 10, and then for channel 4, you press 11. This demonstrates the concept behind a 4-1 multiplexer.

Multiplexers are versatile and find applications in many fields such as telecommunications, computer networking, data storage systems, and digital signal processing. For example, in memory systems, MUXes are used to select specific addresses, while in CPU architectures, they help in routing data among different registers. They are essential for enabling efficient data handling, minimizing resource usage, and simplifying complex digital systems.

If you’d like to see a demo of a 2-1 MUX, watch the video below!