hi, im supose to complete the design of " A'B'CD'+A'B'CD+A'BC'D'+A'BC'D+AB'C'D+AB'CD'+AB'CD+ABCD " or simplifed ver of it " A'BC'+AB'D+B'C+ACD " with a multiplexer and then build the circut at uni any idea on how to do this? ( i have multisim software aswell ) cheers
Ok well begin by simplifying the expression with boolean algebra: A'B'CD'+A'B'CD+A'BC'D'+A'BC'D+AB'C'D+AB'CD'+AB'CD+ABCD ------------------ =========== ------------------ ========== The underlined can be grouped together: A'B'C(D'+D)+A'BC'(D'+D)+AB'C'(D+D')+ACD(B'+B) Since X+X' = 1 because when X=0, X'=1 and vice versa, this results in: A'B'C+A'BC'+AB'C'+ACD -------------- ======== Now factor the underlined and you get: A'(B'C+BC')+A(B'C'+CD) Now what is a mux? A mux is just a selector. It selects between two inputs, X and Y based on the value of a select variable S. Let's take the B'C+BC' statement. Let's arbitrarily pick B as the select variable. If B=0, then BC'=0 and B'C=C. Likewise if B=1, then B'C=0, and BC'=C'. I think you should be able to take it from there. I believe the entire solution will require three muxes.
hi thanks for the reply but i got a diff simplified ans from urs. as i staed in above it was A'BC'+AB'D+B'C+ACD (i used multisim!) now if i put that in the truth table and not worry about the equation ill get this from troth table: 0 0 1 1 1 1 0 0 0 1 1 1 0 0 0 1 E0= 0 E1=1 E2=0 E4=D E5=1 E6=0 E7=D now i used 74151N actually heres what i got in attachment, but it dosent work?! where did i go wrong?! (is the way i did the mux right?) sorry about the balck and green line i forgot to put them in. now the truth table i get from this mux is: 0 0 0 1 1 1 0 0 1 1 1 1 0 0 0 1 what did i do wrong can u guys see what went wrong my head dosent work any more!!!
u first make the truth table from the given function,then draw the implementation table.encircle the min terms.take any one of(A,B,C,D)as data i/p line & the other 3 as select i/p's.then, it's easy na?
hi, u can use a 16 to 1 mux, give the four conrol inputs as s0 A s1 B s2 C s3 D and keep the other inputs at following logic values, e0 0 e1 0 e2 1 e3 0 e4 1 e5 1 e6 0 e7 0 e8 0 e9 1 e10 1 e11 0 e12 1 e13 1 e14 0 e15 1 ur purpose will be solved ps: keep the mux in enable mode