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Digital Demultiplexer

Demultiplexer - Truth Table, Boolean Expression & Logic Circuit | Logicroo

Learn about Digital Demultiplexers with interactive circuit diagrams, truth tables, Boolean expressions, selection logic, logic gate implementation, and digital logic examples.

1-to-4 Demultiplexer

Digital Demultiplexer

A demultiplexer takes a single data input and routes it to exactly one of several outputs, based on the value of its select lines. With two select inputs S1S0, the 1:4 DEMUX steers the data line D through to one of four outputs Y0–Y3 — Y0 = D·S1'S0', Y1 = D·S1'S0, Y2 = D·S1S0', Y3 = D·S1S0. Each output needs an inverted select (NOT), a select-minterm AND, and a data AND — a three gate delay circuit.

Select inputs
Data input
Active line
Y0
Y0 Y1 Y2 Y3
1 0 0 0
Delay
Y0 = D·S1'S0'  Y1 = D·S1'S0  Y2 = D·S1S0'  Y3 = D·S1S0 (3 gate delay — NOT, AND, AND)
Exactly one output carries D for every select combination; the other three are held low.
Truth table (select sweep, current D value)
S1S0Routed toY0Y1Y2Y3