1-to-4 demultiplexer: build and simulate it online
The data bit D goes to the one output the select lines pick.
Build the 1-to-4 demultiplexer in the free online simulator — it checks your circuit automatically.
What you need
- 3 logic switches labelled D, S1, S0
- 4 probes labelled Y0, Y1, Y2, Y3
- a demultiplexer (block or gates)
Step by step
- Inputs and outputs. From the Logic section of the library, drop digital inputs (0/1 boxes) or logic switches for the inputs, and digital outputs or probes for the outputs; give each its label in the inspector (the checker finds them by label). Switches D, S1, S0; Probes Y0, Y1, Y2, Y3
- The demultiplexer. The Demultiplexer block (2 select lines), or four 3-input ANDs with inverters.
- Prove it. All 8 combinations. Only the selected Y follows D
Truth table
| D | S1 | S0 | Y0 | Y1 | Y2 | Y3 |
|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 0 | 0 | 1 | 0 | 0 | 0 | 0 |
| 0 | 1 | 0 | 0 | 0 | 0 | 0 |
| 0 | 1 | 1 | 0 | 0 | 0 | 0 |
| 1 | 0 | 0 | 1 | 0 | 0 | 0 |
| 1 | 0 | 1 | 0 | 1 | 0 | 0 |
| 1 | 1 | 0 | 0 | 0 | 1 | 0 |
| 1 | 1 | 1 | 0 | 0 | 0 | 1 |
Frequently asked questions
How do you build a 1-to-4 demultiplexer?
The data bit D goes to the one output the select lines pick. In short: inputs and outputs, then the demultiplexer, then prove it.
What is the truth table of a 1-to-4 demultiplexer?
It has 3 inputs (D, S1, S0) and 4 outputs (Y0, Y1, Y2, Y3), so 8 rows. The full table is on this page; the Embedded Lab checks all of them against your circuit.
What parts do you need for a 1-to-4 demultiplexer?
a demultiplexer (block or gates) — plus logic switches for the inputs and probes for the outputs.
Can I simulate a 1-to-4 demultiplexer online for free?
Yes. Open it in the BitForBytes Embedded Lab, a free browser-based circuit and logic simulator: drag in the gates, wire them, and press "Check my circuit" — every input combination is simulated and marked for you. No download or sign-up needed.
Part of DSD 22 · Demultiplexers in the free BitForBytes digital system design course.