8x1 Multiplexer
8x1 Multiplexer8x1 multiplexer has 8 data input lines I0, I1, I2, I3, I4, I5, I6, I7, 3 select lines S0, S1, S2 and one output, Y.
Truth Table for 8x1 Multiplexer
Data Select Input
Output
Y
S2
S1
S0
0
0
0
I0
0
0
1
I1
0
1
0
I2
0
1
1
I3
1
0
0
I4
1
0
1
I5
1
1
0
I6
1
1
1
I7
De Multiplexer
De Multiplexer1x8 de multiplexer has 1 input line I, 3 select lines S0,
S1, S2 and 8 outputs Y0, Y1, Y2,
Y3, Y4,Y5,
Y6, Y7
Truth Table of 1x8 DE MUX
Input
Data
S2
S1
S0
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
D
0
0
0
D
0
0
0
0
0
0
0
D
0
0
1
0
D
0
0
0
0
0
0
D
0
1
0
0
0
D
0
0
0
0
0
D
0
1
1
0
0
0
D
0
0
0
0
D
1
0
0
0
0
0
0
D
0
0
0
D
1
0
1
0
0
0
0
0
D
0
0
D
1
1
0
0
0
0
0
0
0
D
0
D
1
1
1
0
0
0
0
0
0
0
D
Multiplexer is a combinational circuit that has maximum of 2n data inputs, ‘n’ selection lines and single output line. One of these data inputs will be connected to the output based on the values of selection lines.
Since there are ‘n’ selection lines, there will be 2n possible combinations of zeros and ones. So, each combination will select only one data input. Multiplexer is also called as Mux.
4x1 Multiplexer
4x1 Multiplexer has four data inputs I3, I2, I1 & I0, two selection lines s1 & s0 and one output Y. The block diagram of 4x1 Multiplexer is shown in the following figure.
One of these 4 inputs will be connected to the output based on the combination of inputs present at these two selection lines. Truth table of 4x1 Multiplexer is shown below.
TRUTH TABLE
Selection LinesOutputS1S0Y00I001I110I211I3
From Truth table, we can directly write the Boolean function for output, Y as
Y=S1′S0′I0+S1′S0I1+S1S0′I2+S1S0I3Y=S1′S0′I0+S1′S0I1+S1S0′I2+S1S0I3
We can implement this Boolean function using Inverters, AND gates & OR gate. The circuit diagram of 4x1 multiplexer is shown in the following figure.
CIRCUIT DAIGRAM
