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This is my NAND with 4 inputs. Only using NAND's how do I extend this to create a 5 input NAND

  • \$\begingroup\$ Where would the fifth input go? There's also no ultimatum that you have explained here. What are you trying to do? \$\endgroup\$
    – user103380
    Aug 29, 2017 at 20:09
  • 1
    \$\begingroup\$ Add two more NANDs. Break the line between the output of either 'inverter' and the final NAND. Mark the output of the 'inverter' as R. Mark the hanging input of the final NAND as S. Now construct an AND out of the two new NANDs. Insert this AND gate, so that R goes to one of its inputs and its output goes to S. The other input to the AND is your added E input. It should be obvious to you why this works. If not, and you explain that you really want to understand, I'll write an explanation. You could also just invert your Q output (to make an AND), feed that to a NAND, adding E as input to that. \$\endgroup\$
    – jonk
    Aug 29, 2017 at 20:12
  • \$\begingroup\$ Throw it away and buy a 74xx30 or 74xx133... \$\endgroup\$
    – Trevor_G
    Aug 29, 2017 at 22:12
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    \$\begingroup\$ @Trevor: some people draw gates on silicon \$\endgroup\$
    – jbord39
    Aug 30, 2017 at 0:16
  • \$\begingroup\$ @jbord39 I know.. I just could not resist.. \$\endgroup\$
    – Trevor_G
    Aug 30, 2017 at 13:16

1 Answer 1



simulate this circuit – Schematic created using CircuitLab

  • \$\begingroup\$ @Tut - Whoops! You're right. For some reason I thought an AND was needed. I've fixed. \$\endgroup\$ Aug 29, 2017 at 20:20
  • \$\begingroup\$ Yeah. That looks better. I'd stated that in my comment at the end. \$\endgroup\$
    – jonk
    Aug 29, 2017 at 20:22

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