I have a 2:1 MUX. It would be designed by using NOR gates. Inputs are X and Y. S, which is data select. When S is 0 F=X , S is 1 F=Y. Until here, okey. I've found $$ F = S'X + SY $$ to make NOR, I've rewritten as $$ F = [(S + X') (S' + Y')]' $$ At this point , I'm stuck how I can make(draw) the expression by using just NOR gates. Actually, It can be drawn via softwares.But, I wonder that how I should think to draw. I need its logic.


1 Answer 1

  • A=input 1, B=input 2, S=switch
  • from A create A' (nor port with 2 times A as input)
  • from B create B' (nor port with 2 times B as input)
  • from S create S' (nor port with 2 times S as input)
  • create X=(S+A')' (nor port with A' as input and S as input)
  • create Y=(S'+B')' (nor port with B' as input and S' as input)
  • create Z=(X+Y)'=((S+A')'+(S'+B')')'
  • create W=Z' (nor port with 2 times Z as input)
  • then W=(((S+A')'+(S'+B')')')'=((S'.A)+(S.B))''=S'.A+S.B
  • \$\begingroup\$ is it right ? i.imgur.com/uoBXXtU.png \$\endgroup\$
    – NewCoder
    Commented Apr 12, 2015 at 22:18
  • \$\begingroup\$ NewCoder's answer needs only 4 NOR gates. Nice. \$\endgroup\$ Commented Apr 13, 2015 at 2:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.