Page 39 - CITS - Electronic Mechanic - TT - 2024
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ELECTRONICS MECHANIC - CITS



           It has two data inputs I0 and I1, one select input S, and one output Y.

           Truth table of 2 X 1 multiplexer









           Boolean Equation : Y = S’I  + SI 1
                                  0










           Working
           •  When S=0,the upper AND GATE will turn ON and lower AND GATE will turn OFF, and so the input I 0 appears
              in the output.
           •  When S=1, the upper AND gate will turn OFF and lower AND gate will turn ON, and so the inputI1 appears in
              the output.
           4 X 1 Multiplexer
           •  It has four data inputs I3, I2, I1 and I0, two select inputs S1 & S0, and one output Y.
           •  Here 2  inputs, i.e. n=2 select lines and m = 1output
                    n=4











                                                       Truth Table

                                     Select Line                              Output Y
                                S1                 S0
                                0                   0                             0
                                0                   1                             1
                                1                   0                            12
                                1                   1                            13

           Working
           •  According to the truth table, when S1 S0=00, the input I0 is selected and routed to the output.
           •  When S1 S0=01, the input I1 is selected and routed to the output.

           •  Similarly, when S1 S0=10, then Y=I2 & when S1 S0=11, then Y=I3.
           Boolean Equation
           Y = S1’S0’I0 + S1’S0I1 + S1S0’I2 + S1S0I3







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