How to design an 8x1 MUX from 4x1 MUX and 2x1 MUX ?


closed as off-topic by Nick Alexeev, Gustavo Litovsky, placeholder, Matt Young, Dave Tweed Oct 5 '13 at 1:46

  • This question does not appear to be about electronics design within the scope defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ IIRC the most you will be able to do is 5 to 1. \$\endgroup\$ – Passerby Oct 4 '13 at 10:27
  • \$\begingroup\$ @Passerby, by cascading 2^n-to-1 is possible for n = 1, 2, ... \$\endgroup\$ – travisbartley Oct 4 '13 at 11:25
  • 1
    \$\begingroup\$ -1. Smells like homework and doesn't explain what has been tried. \$\endgroup\$ – akohlsmith Oct 4 '13 at 12:17
  • 5
    \$\begingroup\$ Smells like a homework problem. Effort to solve not demonstrated. \$\endgroup\$ – Nick Alexeev Oct 4 '13 at 16:37


simulate this circuit – Schematic created using CircuitLab

  • \$\begingroup\$ IMO questions that are obviously homework should not be answered in a way that provides the full answer. Maybe it should be a -1 for that reason, but it feels a bit strange to -1 an answer that is otherwise 100% correct. \$\endgroup\$ – Wouter van Ooijen Oct 4 '13 at 13:18
  • \$\begingroup\$ @WoutervanOoijen, I also thought bout only hinting at the answer, but I don't think the quality of my answers should suffer because a question looks like homework. What if he needs the solution to save a bus of kids from terrorists? Its for the kids, Wouter. Also this a bit of a classic EE interview/study/homework question, and one that needs no explanation. Once you see the answer you understand how MUX cascading works. \$\endgroup\$ – travisbartley Oct 4 '13 at 13:53
  • \$\begingroup\$ I teach this type of stuff myself, and every time a student looks up an answer instead of constructing it for him self an opportunity for learning is lost. (And one day I might travel in an airplane for which he programmed the autopilot.) Hence I disagree with your first sentence: when the question is obviously homework, I'd rather see a 'directional' answer than a final solution. But maybe that's against the spirit of this site. Might make a good meta discussion. (Note that I did not -1 your answer.) \$\endgroup\$ – Wouter van Ooijen Oct 4 '13 at 14:32
  • \$\begingroup\$ @WoutervanOoijen you are totally right and just to enhance that here's the same guy asking virtually the same question but about 2:1MUXES electronics.stackexchange.com/questions/84325/… Here's a chance to vent your downvote!!! \$\endgroup\$ – Andy aka Oct 4 '13 at 17:00
  • \$\begingroup\$ @WoutervanOoijen right you are. Maybe providing the solution isn't in the best interest in the student. But that is what he asked for and I answered the question as asked, in good faith. In the end, it is his responsibility to not cheat, not ours. It is his responsibility to say it is homework, and he doesn't want a full solution. I actually think homework questions are usually the best questions on the site, so I think the stigma against them is unfortunate. Here's the discussion on SO meta.stackexchange.com/questions/10811/… \$\endgroup\$ – travisbartley Oct 5 '13 at 0:48

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