Demultiplexers — Why They Are Called Data Distributors Why is a demultiplexer (DEMUX) commonly referred to as a “data distributor” in digital systems?

Difficulty: Easy

Correct Answer: The input will be distributed to one of the outputs.

Explanation:


Introduction / Context:
A demultiplexer performs the inverse function of a multiplexer. While a MUX selects one of many inputs to drive a single output, a DEMUX routes a single input to exactly one of many outputs based on select lines. This behavior motivates the nickname “data distributor.”



Given Data / Assumptions:

  • One data input line is present.
  • Several output lines are available (e.g., 1-to-4, 1-to-8, 1-to-16).
  • Select lines choose which output receives the input.


Concept / Approach:
For each select-code value, precisely one output is enabled to forward the input signal; the others are disabled (logic 0 or high-impedance depending on the part). Hence, the single input is “distributed” spatially across outputs over time as the select code changes, enabling time-division or address-based routing.



Step-by-Step Solution:
Recognize DEMUX structure: 1 input, n outputs, select lines.Operation: given a select code, connect input to the corresponding output line.Name rationale: this routing distributes a single data stream to different destinations → “data distributor.”Therefore, the correct description is that the input is distributed to one of the outputs.


Verification / Alternative check:
Review standard parts like 74HC138 (decoder used as DEMUX) or dedicated DEMUX devices; truth tables show one active output per select value reflecting the input.



Why Other Options Are Wrong:

  • One of the inputs will be selected for the output: That describes a MUX, not a DEMUX.
  • The output will be distributed to one of the inputs: Direction is reversed.
  • All outputs active simultaneously: Incorrect; exactly one output is selected for normal operation.


Common Pitfalls:
Confusing encoder/decoder/MUX/DEMUX roles; always track the number of inputs vs outputs and the direction of data flow.


Final Answer:
The input will be distributed to one of the outputs.

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