A little electronics question about logical gates

[I like Serena]

Isn't that the definition of $\overline { \overline{ab}c }$ ?

Errr... no?
Why would you think so?

 

[cupid.callin]

Isn't that the definition of $\overline { \overline{ab}c }$ ?

No you can't write it like that but you can use de morgan law to solve that:

\overline{\overline{ab}c}

\overline{\overline{ab}} + \overline{c}

ab + \overline{c}

But using: \overline{ab} = \overline{a} + \overline{b}

 

[Femme_physics]

Funnily, we just used De Morgan Law today...I hope I used it right, but eventually using Boolean algebra I got it to equal 0.

http://img845.imageshack.us/img845/3606/minimizing.jpg

 

[I like Serena]

Looks like you got the hang of boolean algebra!

However, you dropped something when you had $\overline{cc}$ and went to $cc$.EDIT: I missed the abc part which is not right. Fixed it in post #38.

 

[Femme_physics]

Looks like you got the hang of boolean algebra!

However, you dropped something when you had $\overline{cc}$ and went to $cc$.

True, but at the end of the day the result is still 0 cause we got a and a(capped) in the same multiplication line so everything gets nullified, right?

 

[I like Serena]

True, but at the end of the day the result is still 0 cause we got a and a(capped) in the same multiplication line so everything gets nullified, right?

Actually, you don't have $\overline{a}$, but you have $\overline{ab}$.
But yes, in combination with $ab$, everything gets nullified.

 

[Femme_physics]

Actually, you don't have $\overline{a}$, but you have $\overline{ab}$.
But yes, in combination with $ab$, everything gets nullified.

Ah, gotcha! Now I am asked to write the logical value of the function Out, when the values of all the ports
C = '0'
A = B = '1'

But still, everything gets nullified right?

 

[I like Serena]

Hold on, I missed something.

It does not get nullified.

You got $\overline{\overline{ab}c}$, which you took to $abc$, but that is not right.
That changes everything.

 

[Femme_physics]

You're right.

http://img819.imageshack.us/img819/4949/clipboard02gmq.jpg

 

[cupid.callin]

You're right.

http://img819.imageshack.us/img819/4949/clipboard02gmq.jpg

How did you get the forth line??
check it again !

 

[I like Serena]

Could you add parentheses in the 3rd line?