F(A,B,C) = ΠM(0,1,4,6) — Karnaugh map

exam standardentered as maxterms; minimal POS derived

Answer

A′ · B + A · C

Why this example is worth doing

Entered as a list of maxterms rather than minterms, which is how roughly a third of problem sets phrase the question. The tool converts to the ON-set, maps that, and reports both forms. The subtlety the page insists on: minimal POS is obtained by minimising the OFF-set as a sum of products and applying De Morgan to each resulting term, not by dualising the minimal SOP. Dualising computes f(x̄)′, which is a different function, and it is a common and silent bug in competing tools.

Try your own input in the Karnaugh map solver. Group a 2- to 6-variable map yourself and have every group marked right or wrong.

How the answer is reached

Quine–McCluskey

Prime implicants — Quine–McCluskey
#Term
1A′ · B
2B · C
3A · C
Minimum cover — Quine–McCluskey
#Cover
1A′ · B + A · C
Warning:

2 term(s), 4 literal(s); 2 essential prime implicant(s).

Truth table

Truth table — columns #, A, B, C, F
#ABCF
00000
10010
20101
30111
41000
51011
61100
71111

Compare with

Open this example in the Karnaugh map solver

The field arrives filled in with this example’s input.

Note:

Notation this page assumes

  • Symbols: · is AND, + is OR, ⊕ is XOR, a prime or an overline is NOT. The field also takes ∧ ∨ ¬ ~ ! & | and the words.
  • Operator precedence, tightest first: NOT, then AND (including juxtaposition), then XOR/XNOR, then NAND/NOR, then OR, then IMPLIES, then IFF.
  • In a minterm index the first variable is the most significant bit, so over [A, B, C] minterm 5 is A·B̄·C.

Sources

  • Karnaugh, “The Map Method for Synthesis of Combinational Logic Circuits” (1953)
  • Veitch, “A Chart Method for Simplifying Truth Functions” (1952)