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thomas49th
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Homework Statement
Taking the statement Q = A + B + C + D
Rewrite using only NAND (2 inp) and NOT gates
Homework Equations
Well I want to do it all in NAND gates - because we can easily tie NAND inputs to make it a NOT
[tex]\overline{AA} = \overline{A}[/tex]
The Attempt at a Solution
At the moment Q is equal to true if A OR B OR C OR D is true.
I can change OR into a NAND gate quite easily.
[tex]\overline{\overline{(x+y)}} = \overline{\overline{x}\bullet\overline{y}}[/tex]
which is
[tex]x+y = \overline{\overline{x}\bullet\overline{y}}[/tex]
this means I obtain
[tex]\overline{\overline{A}\bullet\overline{B}\bullet\overline{C}\bullet\overline{D}}[/tex]
But this has NOTs and AND logic in, not NAND. I need expressions in NAND which is [tex]\overline{AB}[/tex]
Any hints?
Thanks
Thomas
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