Design a BCD to excess 3 code converter using minimum number of NAND gates.

Hint: use k map techniques.

Ans. Firstly we make the truth table:

After that by using K maps we can get simplified functions for w, x, y, z shown below as:

                                                 NAND gate implementation for simplified function

W = BD + AD + AB' + BC
Through complementing twice we find
W = ((BD + AD + AB' + BC)')'

= ((BD)' . (AD)' . (AB')' . (BC)')' X = BC'D + B'D + B'C

Through complementing twice we find
X = BC'D + B'D + B'C

= ((BC'D)' . (B'D)' . (B'C)')'

Y = C'D' + CD

= ((C'D')' + (CD)')'

Z = D'

Logic diagram for BCD to excess 3 code converter using minimum number of NAND gates