Generador de tablas de verdad

Truth table of a Boolean expression in up to 6 variables, with the canonical sum of products, product of sums, minterms and maxterms.

Actualizado Ejemplos verificados: 8

Operators: not (! ~ ¬ or a trailing '), and (& ·), nand, xor (^ ⊕), or (| +), nor, implies (->), iff (<->). Constants 0 and 1.
Probar
Canonical sum of products
A'·B'·C' + A'·B·C' + A·B'·C' + A·B·C' + A·B·C
Canonical sum of products: A'·B'·C' + A'·B·C' + A·B'·C' + A·B·C' + A·B·C
Canonical product of sums
(A + B + C')·(A + B' + C')·(A' + B + C')
Minterms (rows that are 1)
Σm(0, 2, 4, 6, 7)
Maxterms (rows that are 0)
ΠM(1, 3, 5)
Rows that are true
5
Classification
Contingent

The expression is true in 5 of 8 rows (minterms 0, 2, 4, 6, 7), so its value depends on the inputs.

Columns of the truth table (row 0 on the left)

A
0
0
0
0
1
1
1
1
B
0
0
1
1
0
0
1
1
C
0
1
0
1
0
1
0
1
F
1
0
1
0
1
0
1
1
Tabla de verdad Filas: 8
RowABCF
00001
10010
20101
30110
41001
51010
61101
71111
Cómo se calcula S
  1. Read with operator precedence

    (A∧B)∨¬C\left(A \land B\right) \lor \lnot C

    not binds tightest, then and/nand, xor, or/nor, implies (grouped from the right), and iff last.

  2. Evaluate all 8 rows

    Each row sets A, B, C to one combination of 0s and 1s, counting in binary with A as the most significant bit; the row number is the minterm index.

  3. Minterms and maxterms

    F=∑m(0,2,4,6,7)=∏M(1,3,5)F = \sum m(0, 2, 4, 6, 7) = \prod M(1, 3, 5)
  4. Canonical sum of products

    F=A‾B‾C‾+A‾BC‾+AB‾C‾+ABC‾+ABCF = \overline{A} \overline{B} \overline{C} + \overline{A} B \overline{C} + A \overline{B} \overline{C} + A B \overline{C} + A B C

    One product term for each row where F = 1; a bar means the variable is 0 in that row.

  5. Canonical product of sums

    F=(A+B+C‾)(A+B‾+C‾)(A‾+B+C‾)F = (A + B + \overline{C})(A + \overline{B} + \overline{C})(\overline{A} + B + \overline{C})

    One sum term for each row where F = 0; each term is 0 only in its own row.

Acerca de Generador de tablas de verdad

A truth table lists the value of a Boolean expression for every combination of its inputs: 2ⁿ rows for n variables, so 8 rows for A, B and C. Each row where the expression is 1 is a minterm, and the OR of those minterms is the canonical sum of products; each row where it is 0 is a maxterm, and the AND of the maxterms is the canonical product of sums. Both describe the same function.

Digital logic and computer science students use it to check circuit designs, simplify conditions and verify logic laws. The default, (A and B) or not C, is true in 5 of 8 rows, minterms 0, 2, 4, 6 and 7, and false in rows 1, 3 and 5.

Up to 6 variables (64 rows) are accepted. Precedence runs not, and/nand, xor, or/nor, implies (grouped from the right), then iff; symbols such as !, &, | and ^ also work. An expression true in every row is a tautology, and one false in every row is a contradiction.

Ejemplos resueltos

A and B

Boolean expression
A and B
Canonical sum of products
A·B
Minterms (rows that are 1)
Σm(3)
Rows that are true
1
Classification
Contingent

Fuente de comprobación: Python itertools.product over (A, B): only A=1, B=1 is true

A xor B

Boolean expression
A xor B
Canonical sum of products
A'·B + A·B'
Minterms (rows that are 1)
Σm(1, 2)
Canonical product of sums
(A + B)·(A' + B')

Fuente de comprobación: Python itertools.product with a != b

A implies B

Boolean expression
A -> B
Minterms (rows that are 1)
Σm(0, 1, 3)
Maxterms (rows that are 0)
ΠM(2)
Canonical product of sums
(A' + B)

Fuente de comprobación: Python itertools.product with (not a) or b

Tautology: A or not A (edge case)

Boolean expression
A or not A
Classification
Tautology
Canonical product of sums
1
Rows that are true
2

Fuente de comprobación: Law of excluded middle; Python check over A in (0, 1)

Preguntas

How do you make a truth table?

List every combination of the inputs by counting in binary: 2 variables give 4 rows, 3 give 8, and 6 give 64. Then evaluate the expression in each row, working from the innermost operation outward. For (A and B) or not C, the row A = 1, B = 1, C = 1 gives (1 and 1) or 0 = 1, while A = 0, B = 0, C = 1 gives 0 or 0 = 0.

What are minterms and maxterms?

A minterm is an AND of every variable, each plain or negated, that is 1 in exactly one row; a maxterm is an OR of every variable that is 0 in exactly one row. Row numbers index them: for A, B and C, minterm 6 is A·B·C′ and maxterm 1 is (A + B + C′). A function is the OR of its minterms and, equally, the AND of its maxterms.

What is the difference between sum of products and product of sums?

A sum of products (SOP) ORs together AND terms, one for each row where the function is 1; a product of sums (POS) ANDs together OR terms, one for each row where it is 0. A xor B is A′·B + A·B′ as a sum of products and (A + B)·(A′ + B′) as a product of sums. Both are complete; the shorter one is whichever has fewer rows to cover.

What is a tautology in logic?

An expression that is true in every row of its truth table, whatever the inputs. A or not A, the law of excluded middle, is the simplest; (A → B) or (B → A) is another. The opposite, false in every row, is a contradiction, such as A and not A, and anything true in some rows but not others is called contingent.

When is A implies B true?

A → B is false only when A is true and B is false; in the other three rows it is true. Its truth table therefore has minterms 0, 1 and 3 and a single maxterm, 2, and it is equivalent to not A or B and to its contrapositive, not B → not A. A chain such as A → B → C groups from the right, as A → (B → C).

¿Qué precisión tiene «Generador de tablas de verdad»?

La precisión depende de tus datos y de los supuestos del método. El cálculo decimal usa 50 cifras significativas, pero las estimaciones, los métodos numéricos y los datos de origen pueden ser menos precisos; el redondeo mostrado no elimina esos límites. Ejemplos resueltos comprobados con fuentes independientes: 8. Por ejemplo, «A and B» se comprueba con Python itertools.product over (A, B): only A=1, B=1 is true.

¿De dónde procede el método?

Wolfram MathWorld — Truth Table; Wikipedia — Canonical normal form (minterms and maxterms).

Acerca de esta calculadora

F=∑F(m)=1m(sum of minterms)=∏F(M)=0M(product of maxterms)\begin{aligned} F &= \sum_{F(m)=1} m \quad \text{(sum of minterms)} \\[4pt] &= \prod_{F(M)=0} M \quad \text{(product of maxterms)} \end{aligned}

Fuentes

  1. Wolfram MathWorld — Truth Table
  2. Wikipedia — Canonical normal form (minterms and maxterms)

Verificado con las referencias

Esta calculadora incluye 8 ejemplos resueltos con respuestas de fuentes independientes. Forman parte del conjunto de pruebas y también puedes ejecutarlos aquí.

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