# Two boolean functions

Discussion in 'Homework Help' started by mannycalavera, Jan 26, 2009.

1. ### mannycalavera Thread Starter New Member

Jan 26, 2009
2
0
Hello, i need some help with a boolean function, my task is to use only a) NAND gates and b) only NOR gates. The function is
F=A'BC' + A'BC+AB'C (i use the ' notification for NOT)

So i have to convert it to solely NAND gates. Any suggestions?
I try to implement Demorgans law, but i receive a questionable result.
I would be very thankfull for anykind of hints/solutions?
P.S. im not trying just to copy the homework, but to understand it

2. ### vvkannan Active Member

Aug 9, 2008
138
11
hello mannycalavera,

implement the boolean expression using all gates first(i.e AND,OR,NOT)

now replace the single input NOT gate by NAND by splitting the input into two inputs)

now remember that NAND gate is AND added with NOT and hence when you see a AND add two NOT gates after that(2 NOTs will not make any difference).
REPLACE the AND and 1 NOT with NAND( DEMORGAN'S) and the other NOT as described in above step.

remember a NOT before OR can be replaced by NAND.so add 2 NOTs before OR.
replcae 1 NOT and OR with NAND and the other NOT as described previously.

similar procedure can be adopted for NOT but remember

NOT added before AND is NOR
NOT added after OR is NOR

3. ### hgmjr Moderator

Jan 28, 2005
9,030
214
It might help you to read through the material in the AAC ebook on Boolean Algebra. The presentation is straightforward and relatively easy to follow.

hgmjr

4. ### Ratch New Member

Mar 20, 2007
1,068
3
mannycalavera,

The first thing you should do is simplify the Boolean expression you want to implement.

A'BC' + A'BC+AB'C
A'B(C' + C) + AB'C
A'B + AB'C

Ratch

5. ### mannycalavera Thread Starter New Member

Jan 26, 2009
2
0
still i cannot reach the solution

6. ### Skeebopstop Active Member

Jan 9, 2009
358
3
Using Ratch's simplification:

A'B + ABC'

The attached circuit should do this.

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