# Boolean Expression Extraction

Discussion in 'Homework Help' started by *.*.*AnUm*.*.*, Aug 1, 2015.

1. ### *.*.*AnUm*.*.* Thread Starter New Member

Apr 21, 2015
16
0
Hi,

See, is my concept correct ?

In this k map, we can't make group of three 1's because all variables are changing, if we make group of these three 1's. group of 1's we can't make is highlighted.

Thanks!

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2. ### tshuck Well-Known Member

Oct 18, 2012
3,527
675
The reason why depends on what the relationships are between the boxes in the map. Try to reduce the expression using Boolean logic and compare the results to that of the K-map - this should grant you an idea of why and how a K-map works and why it uses such an odd numbering scheme.

3. ### WBahn Moderator

Mar 31, 2012
20,057
5,644
The key is in understanding what a K-map is used for. The groupings identify signals that do not matter for that grouping, meaning that if you change that variable that you don't change the output. In your grouping of three, it would appear that changing A doesn't change the output and changing B doesn't change the output. But yet if you change A and B so that both are LO, you change the output. Thus it is not a valid logic minimization.

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