# Help! POS equation to a K-map

Discussion in 'Homework Help' started by diamondking3, Mar 16, 2011.

1. ### diamondking3 Thread Starter New Member

Mar 16, 2011
14
0
Hi Guys,

I have a question that im stuck on.
The equation is: (A+B'+C) . (B+C'+D)
How do i turn this into a k-map? where the is no truth table given to me?

Thank you very much!

2. ### diamondking3 Thread Starter New Member

Mar 16, 2011
14
0
-POS equation: (A+B'+C).(B+C'+D) ( ' represtent bar. )
-Create a K-Map
-How many minterms and maxterms are present in the K-Map?

3. ### syed_husain Active Member

Aug 24, 2009
61
5
u got 4 input namely A,B,C, and D. that is there will be 2^4 or 16 possible combination (0000 to 1111) . write down all the combination then plug them in the equation provided. u will construct the truth-table. from there transfer it to the 4 variable k-map.

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4. ### diamondking3 Thread Starter New Member

Mar 16, 2011
14
0
ok.. thanks! i know how to do all those excpet how do i write down the output from the truth table? can u give me an example?

5. ### syed_husain Active Member

Aug 24, 2009
61
5
i forgot 2 mention that ur equation is not in standard POS format i.e. u need all the variables in each term (in first term varible "d" is missing and in 2nd term "a" is missing).

have u completed the truth table? from there chk when output is "1" that will be ur minterm and the rest maxterm i.e. output "0". (dont forget max and min r complement to each other)

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6. ### diamondking3 Thread Starter New Member

Mar 16, 2011
14
0
hmmm... How to do the truth table if "D" is missing in the first term and "A" is missing in the second term?

is it like this?

A B C D X
0 0 0 0 0
0 0 0 1 0
0 0 1 0 0
0 0 1 1 0
0 1 0 0 0
0 1 0 1 1
0 1 1 0 0
0 1 1 1 0
1 0 0 0 0
1 0 0 1 0
1 0 1 0 0
1 0 1 1 1
1 1 0 0 0
1 1 0 1 0
1 1 1 0 0
1 1 1 1 0

7. ### syed_husain Active Member

Aug 24, 2009
61
5
yep it should be like that. now ur minterm is (5,11) and rest is maxterm.

regarding standard POS format: regarding ur problem this is not necessary 2 find out the standard format but if u r asked to find the output function from k-map or draw the combinational cct u must use standard format either POS or SOP.

i solved the function as standard POS format. c the attachment.

hope this will help.

cheers

• ###### POS.doc
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26 KB
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24
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8. ### diamondking3 Thread Starter New Member

Mar 16, 2011
14
0
GREAT! Thank you!!!