Page 40 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

Demultiplexer

Illustration of demultiplexer
• It has one input common data, ‘n’ select lines and ‘m’ output lines.
• A demultiplexer performs the reverse operation of a multiplexer i.e. it receives one input and distributes it over
several outputs.

• At a time only one output line is selected by the select lines and the input is transmitted to the selected output
line.
• Relation between ‘n’ output lines and m select lines is as follows:

n = 2 m
1 X 4 Demultiplexer
• 1 to 4 Demultiplexer has one data input F; select line inputs a,b and four outputs A, B, C &D.
• The select lines control the data to be routed. It helps in selecting the output on which the data will be routed.
Switch Representation

Based on the switch control, the input is routed to particularoutput.
Truth table of 1 X 4 demultiplexer
Boolean Equation
A= Fb′a′; B = Fb′a; C= ba′; D=Fba
Working

• When ab=”00”, the input data F is routed to the output A

25
CITS : E & H - Electronics Mechanic - Lesson 9 - 29