# Quine McCluskey method help

#### Andreea Blaga ت

Joined Jun 26, 2015
15
Hello,
I am currently studying for my exam, and I came across using Quine McCluskey method but with conjuctive canonical form rather than disjunctive. I googled it a lot and visited various sites, but didnt find anything useful. I have no idea how to solve this. Does anyone know something about it?
Any help will be much appreciated, thanks in advance.

#### Papabravo

Joined Feb 24, 2006
12,702
The basis for the method is to look for patterns in the input variables that allow you to implement the logic function with fewer terms and fewer factors in each term. It is also called the "method of prime implicants".

#### Andreea Blaga ت

Joined Jun 26, 2015
15
The basis for the method is to look for patterns in the input variables that allow you to implement the logic function with fewer terms and fewer factors in each term. It is also called the "method of prime implicants".
Thank you for your reply. Yes, indeed, I do know the logic behind it. But what I dont really understand nor find is how can you implement it by using conjuctive canonical terms, like the steps concerning the method and such.

#### Papabravo

Joined Feb 24, 2006
12,702
It is all about pattern recognition. Using Boolean variables A, B, C, and D the patterns can be hard to see. You are looking for:
... + ABCD + ABCD* +...
In this case D is a don't care because you have both the factor D and it's complement, and the prime implicant is ABC.
Some people find it easier to look at a binary representation of the terms.
ABCD = 1111
ABCD* = 1110
so ... + 1111 + 1110 ... = ...+ 111x + ...
Do you get the idea?

#### Andreea Blaga ت

Joined Jun 26, 2015
15
It is all about pattern recognition. Using Boolean variables A, B, C, and D the patterns can be hard to see. You are looking for:
... + ABCD + ABCD* +...
In this case D is a don't care because you have both the factor D and it's complement, and the prime implicant is ABC.
Some people find it easier to look at a binary representation of the terms.
ABCD = 1111
ABCD* = 1110
so ... + 1111 + 1110 ... = ...+ 111x + ...
Do you get the idea?
Yes, indeed. I understand where this is going. Thank you.

#### Andreea Blaga ت

Joined Jun 26, 2015
15
It might help you out if you take a bit of time learning about how to switch between SOP and POS forms and also about consensus terms. It might give you needed perspective to see how it all fits together.

Yes, thank you. This helps quite a bit. So, to conclude it,all I have to do is pretty much convert the minterms into maxterms, or to say the conjuctive form into disjunctive form and apply the algorithm?

#### Papabravo

Joined Feb 24, 2006
12,702
"The rain in Spain falls mainly on the plain"

By George I think she's got it!