Decoder (2-to-4)

Use the combinational 2-to-4 Decoder to convert a two-bit unsigned input into four active-HIGH one-hot outputs.

Overview

The 2-to-4 Decoder converts a two-bit unsigned input into four active-HIGH one-hot outputs.

DigiSim Interface

Direction	Pins	Behavior
Input	A, B	Binary code; A is the least-significant bit.
Output	Y0–Y3	Active-HIGH one-hot result.

Decode Table

There is no enable input. For defined binary inputs exactly one output is HIGH. Released inputs sample as LOW; driven unknowns are evaluated by binary completion, so outputs known to be LOW may remain defined while other outputs become X.

Simulation Boundary

The component is a fixed combinational decoder. It is not memory, a demultiplexer with a data input, or a configurable active-level device.

Learning Path

Prerequisites

AND Gate NOT Gate

Next Steps

Decoder (3-to-8)Encoder (4-to-2)

Frequently Asked Questions

What is a decoder?

A decoder converts an n-bit binary input to 2^n outputs, where only one output is active (one-hot encoding). 2 inputs produce 4 outputs, 3 inputs produce 8 outputs.

What is one-hot encoding?

Only one output line is HIGH at a time. For input 10 (binary 2), output Y2 is HIGH while Y0, Y1, Y3 are LOW.