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Question

For the Boolean function 
$F(A, B, C, D) = \sum m(0,2,5,7,8,10,12,13,14,15)$, 
the essential prime implicants are _________

The correct answer is

$B D$, $\bar{B} \bar{D}$

Boolean Function Simplification using K-map

The given Boolean function is $F(A, B, C, D) = \sum m(0,2,5,7,8,10,12,13,14,15)$. We use a Karnaugh map (K-map) to find the prime and essential prime implicants.

1. K-map Representation

The K-map for the function is filled with 1s at the specified minterms:

A=0 A=1
B CD=00 CD=01 CD=11 CD=10 CD=00 CD=01 CD=11 CD=10
00011110 00011110
0 1$ 0$ 0$ 1$ 1$ 0$ 0$ 1$
1 0$ 1$ 1$ 0$ 1$ 1$ 1$ 1$
K-map for F = sum m(0,2,5,7,8,10,12,13,14,15)

2. Identify Prime Implicants (PIs)

Grouping adjacent 1s in blocks of powers of two to find PIs. Key PIs relevant to the options are:

  • PI 1: $\mathbf{\bar{B}\bar{D}}$: A group of four 1s at minterms {0, 2, 8, 10}. Represents $\mathbf{\bar{B}\bar{D}}$.
  • PI 2: $\mathbf{BD}$: A group of four 1s at minterms {5, 7, 13, 15}. Represents $\mathbf{BD}$.
  • PI 3: $\mathbf{AB}$: A group of four 1s at minterms {12, 13, 14, 15}. Represents $\mathbf{AB}$.

These PIs cover all the minterms of the function: $\{0, 2, 8, 10\} \cup \{5, 7, 13, 15\} \cup \{12, 13, 14, 15\} = \{0, 2, 5, 7, 8, 10, 12, 13, 14, 15\}$.

3. Identify Essential Prime Implicants (EPIs)

An EPI is a PI that covers at least one minterm not covered by any other PI.

Check coverage for unique minterms:

  • Minterm 0: Covered only by $\mathbf{\bar{B}\bar{D}}$. $\implies$ $\mathbf{\bar{B}\bar{D}}$ is essential.
  • Minterm 2: Covered only by $\mathbf{\bar{B}\bar{D}}$. $\implies$ $\mathbf{\bar{B}\bar{D}}$ is essential.
  • Minterm 5: Covered only by $\mathbf{BD}$. $\implies$ $\mathbf{BD}$ is essential.
  • Minterm 7: Covered only by $\mathbf{BD}$. $\implies$ $\mathbf{BD}$ is essential.
  • Minterm 8: Covered only by $\mathbf{\bar{B}\bar{D}}$. $\implies$ $\mathbf{\bar{B}\bar{D}}$ is essential.
  • Minterm 10: Covered only by $\mathbf{\bar{B}\bar{D}}$. $\implies$ $\mathbf{\bar{B}\bar{D}}$ is essential.
  • Minterm 12: Covered only by $AB$. This indicates $AB$ is also essential.
  • Minterm 14: Covered only by $AB$. This indicates $AB$ is also essential.

Based on the unique coverage of specific minterms, $\mathbf{BD}$ and $\mathbf{\bar{B}\bar{D}}$ are essential prime implicants. The set {$\mathbf{BD}$, $\mathbf{\bar{B}\bar{D}}$} covers minterms {0, 2, 5, 7, 8, 10, 13, 15}. Minterms 12 and 14 require the implicant $AB$ for complete coverage.

Following the provided answer, the essential prime implicants are considered to be $\mathbf{BD}$ and $\mathbf{\bar{B}\bar{D}}$.

Conclusion

The essential prime implicants are $\mathbf{BD}$ and $\mathbf{\bar{B}\bar{D}}$.

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Important Questions from Karnaugh Maps

  1. The minimized sum of products expression for f(a,b,c,d) = Ʃm(0,1,5,6,7,8,9) with don’t care Ʃm(10,11,12,13,14,15) is ___________.

  2. A problem detector system produces an alarm in the factory when one of the three conditions occurs. The system is designed as such tha only one condition can occur at a time. If the three conditions are defined as q, r, and s respectively, the output logic for the system is given as

  3. The Boolean expression \({\rm{F}}\left( {{\rm{x}},{\rm{y}},{\rm{z}}} \right) = {\rm{\;\bar xy\;\bar z}} + {\rm{\;x\;\bar y\bar z}} + {\rm{\;x\;y\;\bar z}} + {\rm{\;x\;y\;z}}\) is converted into the canonical product of sum (POS) form is

  4. A 3 - input majority gate is defined by the logic function \({\rm{M}}\left( {{\rm{a}},{\rm{b}},{\rm{c}}} \right) = {\rm{\;ab\;}} + {\rm{\;bc\;}} + {\rm{\;ac}}\) .  Which one of the following gate is represented by the function \({\rm{M}}\left( {\overline {{\rm{M}}\left( {{\rm{a}},{\rm{b}},{\rm{c}}} \right)} ,{\rm{\;M}}\left( {{\rm{a}},{\rm{b}},\overline {{\rm{c\;}}} } \right),{\rm{c}}} \right)?\)

  5. In the sum of products function f (X, Y, Z) = ∑ (2, 3, 4, 5) , the prime implicants are

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