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Logic circuit generator: Boolean expression to gate diagram (SVG)

Turn a Boolean expression into a logic gate diagram, drawn by the engine as SVG with standard gate shapes, labelled ports and one node per operator.

Everything runs in your browser; nothing is sent anywhere.

The diagram is the engine's logical dependency graph: an input node for each variable, a gate for each operator (NOT, AND, OR, XOR, NAND, NOR, XNOR, implication and biconditional drawn as their gate forms), and an output node for the result. Fan-out is shown by one input feeding several gates. The layout is automatic; the picture is not a timing diagram or a physical layout, and the page says so.

The SVG is generated without scripts or external references, so it can be saved, embedded in a document or pasted into a slide. In the app, the same diagram is editable: you can add gates, connect ports and watch live values flow through it as you toggle inputs.

The expression's plain-language reading sits beside the diagram, because a diagram alone can hide the grouping: A OR B AND C and (A OR B) AND C draw differently, and the reading says which one you have.

Limits

  • Truth tables up to 12 inputs (4096 rows).
  • Karnaugh maps up to 4 effective variables.
  • Normal forms up to 4096 terms; expressions up to 20000 characters and 64 inputs.

How to write expressions

Write inputs as names (member, A, credit_ok) and combine them with AND, OR, NOT, XOR, -> (implies), <-> (if and only if), NAND(a, b), NOR(a, b), XNOR(a, b), or the symbols &&, ||, !, ∧, ∨, ¬, ·, +, ′. Minterm and maxterm forms work too: Σm(A, B, C; 1, 3), ΠM(A, B; 0). Precedence: NOT, then AND, then XOR, then OR, then ->, then <->; use parentheses to be explicit. =, ==, ^, &, | and ~ are rejected with a repair.

Example

f := (A AND B) OR (Cin AND (A XOR B)) · output

Exact checks

Always true (tautology)? No Counterexample: A = F, B = F, Cin = F · Exhaustively checked and solver cross-checked · 1 rows
Always false (contradiction)? No Counterexample: A = F, B = T, Cin = T · Exhaustively checked and solver cross-checked · 4 rows
Can be true? Yes Example assignment: A = F, B = T, Cin = T · Exhaustively checked and solver cross-checked · 4 rows

Truth table (8 rows)

Logic circuit generator: Boolean expression to gate diagram (SVG)
#ABCinf
0FALSEFALSEFALSEFALSE
1FALSEFALSETRUEFALSE
2FALSETRUEFALSEFALSE
3FALSETRUETRUETRUE
4TRUEFALSEFALSEFALSE
5TRUEFALSETRUETRUE
6TRUETRUEFALSETRUE
7TRUETRUETRUETRUE

Plain-language reading

Beginnerf is true exactly when at least one of the following holds (both may hold):
1. both A and B are true
2. both of the following hold:
2.1. Cin is true
2.2. exactly one of A and B is true (not both)
In every other case, f is false.
About the operators:
- OR is inclusive: it is true when at least one part is true, including when several are.
- AND is true only when all of its parts are true.
- XOR (exclusive or) is true when exactly one of its two parts is true.
Intermediatef is true exactly when at least one of the following holds (both may hold):
1. both A and B are true
2. both of the following hold:
2.1. Cin is true
2.2. exactly one of A and B is true (not both)
In every other case, f is false.
Advancedf is true exactly when at least one of the following holds (both may hold) [inclusive disjunction ∨]:
1. both A and B are true [conjunction ∧]
2. both of the following hold [conjunction ∧]:
2.1. Cin is true
2.2. exactly one of A and B is true (not both) [exclusive disjunction ⊕]
In every other case, f is false.
Formal notation: (A ∧ B) ∨ (Cin ∧ (A ⊕ B))

Logic diagram

Logic circuit generator: Boolean expression to gate diagram (SVG) Logic circuit generator: Boolean expression to gate diagram (SVG) A B Cin f OR AND AND XOR
Logic circuit generator: Boolean expression to gate diagram (SVG) Logic circuit generator: Boolean expression to gate diagram (SVG) A B Cin f OR AND AND XOR

Simplification, step by step

The engine found no law that shortens this expression; it is already as short as its rewriting laws can make it.

(A AND B) OR (Cin AND (A XOR B))

Karnaugh map

A \ BCin
00
01
11
10
0
0m0
0m1
1m3
0m2
1
0m4
1m5
1m7
1m6
  1. cells m6, m7A AND B
  2. cells m5, m7A AND Cin
  3. cells m3, m7B AND Cin
(A AND B) OR (A AND Cin) OR (B AND Cin) · Derived (A AND B) OR (A AND Cin) OR (B AND Cin). Exactly equivalent on every assignment.

Minterms and maxterms

f(A, B, Cin) = Σm(3, 5, 6, 7)f(A, B, Cin) = ΠM(0, 1, 2, 4)

Variable order: A, B, Cin · 8 rows

Normal forms

Conjunctive normal form (CNF)

(A OR B) AND (A OR Cin) AND (B OR Cin)

3 clauses, 6 literals · complete · XOR elimination ×1, Distribution ×1, Complement ×2, Idempotence ×1

Disjunctive normal form (DNF)

(A AND B) OR (A AND NOT B AND Cin) OR (NOT A AND B AND Cin)

3 terms, 8 literals · complete · XOR elimination ×1, Distribution ×1

NAND-only and NOR-only

NAND-only form

NAND(NAND(A, B), NAND(Cin, NAND(NAND(A, NAND(B, B)), NAND(NAND(A, A), B))))

8 gates · verified equivalent on every row

NOR-only form

NOR(NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(Cin, Cin), NOR(NOR(NOR(A, A), B), NOR(A, NOR(B, B))))), NOR(NOR(NOR(A, A), NOR(B, B)), NOR(NOR(Cin, Cin), NOR(NOR(NOR(A, A), B), NOR(A, NOR(B, B))))))

23 gates · verified equivalent on every row

The same rule as code

Python
# -*- coding: utf-8 -*-
# Generated by Tangibool (tangibool.python/1). Do not edit by hand; regenerate from the source revision.
# Model: not stated
# Source revision: reference
# Interpretation status: not stated
"""Tangibool evaluator (decision model).

Generated deterministically from the validated Boolean model; it evaluates exactly that
model. It does not establish that the model is a complete, legal, or safe statement of a
real-world rule, and evaluating examples does not verify the rule.

Source revision: reference
Interpretation status: not stated
Exporter: 1.0.0 (format tangibool.python/1; engine 1.0.0; semantics tangibool-semantics/1)
Logic digest: 11c1109a9bff240df1857b52b71474b4908db824f8f3f9a0373b88b059d010b6
Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78

Inputs (dict keys, declared order) and generated parameter names:
    'A' -> input_A
    'B' -> input_B
    'Cin' -> input_Cin

Outputs (declared order) and their functions:
    'f' -> output_f(inputs)

Assumptions (the declared scope, checked by in_scope(inputs)):
    none; every complete assignment is in scope.

Input contract:
    Every required input must be exactly True or False (type(value) is bool). Missing
    inputs, None, strings, integers (including 0 and 1), and keys that are not declared
    inputs raise InputError before anything is evaluated, including inputs that a
    short-circuiting operator would never read. Results are always bool.

Scope:
    Decision functions raise OutOfScopeError when the inputs violate an assumption; an
    out-of-scope assignment is never turned into a False result. Pass check_scope=False
    to evaluate without the scope check, and use in_scope(inputs) to test it separately.

Usage:

    import tangibool_model as model

    model.evaluate({'A': False, 'B': False, 'Cin': False})
    # -> {'f': False}
    model.output_f({'A': False, 'B': False, 'Cin': False})
    # -> False
    model.evaluate({'A': 1, 'B': False, 'Cin': False})
    # raises InputError: 1 is an int, not a bool
"""

import collections.abc as _abc
from typing import Dict, Mapping, Tuple

__all__ = [
    "MODEL_INFO",
    "IDENTIFIER_MAP",
    "INPUT_NAMES",
    "OUTPUT_NAMES",
    "ASSUMPTIONS",
    "InputError",
    "OutOfScopeError",
    "minterm_index",
    "in_scope",
    "evaluate",
    "output_f",
]

MODEL_INFO = {
    "format": "tangibool.python/1",
    "mode": "decision",
    "model": None,
    "revision": "reference",
    "interpretation": None,
    "exporter": "1.0.0",
    "engine_version": "1.0.0",
    "semantics_version": "tangibool-semantics/1",
    "logic_digest": "11c1109a9bff240df1857b52b71474b4908db824f8f3f9a0373b88b059d010b6",
    "assumptions_digest": "d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78",
    "primary_output": "f",
    "unused_inputs": (),
    "subcircuits": (),
}

# Stable ID -> generated identifier (reversible mapping; names are exact, escaped strings).
IDENTIFIER_MAP = {
    "v_0295965d44fd": {"kind": "input", "name": "A", "identifier": "input_A"},
    "v_1b5bf3b38ee6": {"kind": "input", "name": "B", "identifier": "input_B"},
    "v_d85e4452d9c6": {"kind": "input", "name": "Cin", "identifier": "input_Cin"},
    "f_8769ad1f6fc1": {"kind": "output", "name": "f", "identifier": "output_f"},
}

INPUT_NAMES = ("A", "B", "Cin")
OUTPUT_NAMES = ("f",)
ASSUMPTIONS = ()

_DECLARED_INPUTS = frozenset(INPUT_NAMES)
_SCOPE_INPUTS = ()
_ASSUMPTION_FORMULAS = {entry["name"]: entry["formula"] for entry in ASSUMPTIONS}


class InputError(ValueError):
    """Raised when inputs are missing, undeclared, or not exactly True/False.

    Every required input must satisfy type(value) is bool. Missing inputs, None, strings,
    integers (including 0 and 1), and keys that are not declared inputs are rejected before
    anything is evaluated. A missing input is never treated as False. The individual problems
    are listed in the problems attribute.
    """

    def __init__(self, problems):
        self.problems = tuple(problems)
        super().__init__("Invalid inputs: " + "; ".join(self.problems))


class OutOfScopeError(ValueError):
    """Raised when the inputs violate the model's assumptions (its declared scope).

    Outside its assumptions the rule has no decision: this error is never a False result.
    The names of the violated assumptions are in the violated attribute.
    """

    def __init__(self, violated):
        self.violated = tuple(violated)
        details = ", ".join(name + " (" + _ASSUMPTION_FORMULAS.get(name, "?") + ")" for name in self.violated)
        super().__init__(
            "Out of scope: the inputs violate "
            + ("assumption " if len(self.violated) == 1 else "assumptions ")
            + details
            + ". The rule has no decision outside its assumptions; this is not a False result."
        )


def _short_repr(value: object) -> str:
    text = repr(value)
    return text if len(text) <= 60 else text[:57] + "..."


def _checked_inputs(inputs: Mapping[str, bool], required: Tuple[str, ...], check_scope: bool) -> Dict[str, bool]:
    """Validate inputs strictly before anything is evaluated and return a plain copy."""
    if type(check_scope) is not bool:
        raise TypeError("check_scope must be True or False")
    if not isinstance(inputs, _abc.Mapping):
        raise InputError(["inputs must be a mapping from input names to True/False, got " + type(inputs).__name__])
    problems = []
    for key in inputs:
        if type(key) is not str or key not in _DECLARED_INPUTS:
            declared = ", ".join(repr(name) for name in INPUT_NAMES) or "none"
            problems.append("undeclared input " + _short_repr(key) + " (declared inputs: " + declared + ")")
    needed = tuple(required) + (_SCOPE_INPUTS if check_scope else ())
    for name in needed:
        if name not in inputs:
            problems.append("missing required input " + repr(name))
    for key, value in inputs.items():
        if type(key) is str and key in _DECLARED_INPUTS and type(value) is not bool:
            problems.append(
                "input " + repr(key) + " must be True or False (type bool), got "
                + type(value).__name__ + " " + _short_repr(value)
            )
    if problems:
        raise InputError(list(dict.fromkeys(problems)))
    return dict(inputs.items())


def _require_bool_args(function: str, pairs: Tuple[Tuple[str, object], ...]) -> None:
    problems = [
        "argument " + repr(name) + " of " + function + " must be True or False (type bool), got "
        + type(value).__name__ + " " + _short_repr(value)
        for name, value in pairs
        if type(value) is not bool
    ]
    if problems:
        raise InputError(problems)


def minterm_index(*values: bool) -> int:
    """Row index of an assignment over a declared variable order.

    The first value is the most significant bit, so all-False is row 0. Used for indexed
    minterm (sum) and maxterm (product) forms.
    """
    index = 0
    for value in values:
        if type(value) is not bool:
            raise InputError(["minterm_index() takes True/False values, got " + type(value).__name__ + " " + _short_repr(value)])
        index = index * 2 + (1 if value else 0)
    return index


def _scope_values(values: Dict[str, bool]) -> Tuple[Tuple[str, bool], ...]:
    """Value of every enabled, confirmed assumption for validated inputs, in declared order."""
    return ()


def _require_in_scope(values: Dict[str, bool]) -> None:
    violated = tuple(name for name, holds in _scope_values(values) if not holds)
    if violated:
        raise OutOfScopeError(violated)


def in_scope(inputs: Mapping[str, bool]) -> bool:
    """True when the inputs satisfy every assumption (the model's declared scope).

    Requires the inputs the assumptions read; raises InputError for invalid inputs.
    """
    values = _checked_inputs(inputs, (), True)
    return all(holds for _, holds in _scope_values(values))


# ---- Formula bodies (inputs are validated by the public functions below) ----


def _compute_output_f(input_A: bool, input_B: bool, input_Cin: bool) -> bool:
    """Decision output 'f': (A AND B) OR (Cin AND (A XOR B))"""
    return (input_A and input_B) or (input_Cin and (input_A != input_B))


# ---- Public API ----


def output_f(inputs: Mapping[str, bool], *, check_scope: bool = True) -> bool:
    """Decision output 'f' (stable ID f_8769ad1f6fc1).

    'f' := (A AND B) OR (Cin AND (A XOR B))

    Required inputs: 'A', 'B', 'Cin'.
    Raises InputError for missing, undeclared, or non-bool inputs, and OutOfScopeError
    when check_scope is True and the inputs violate an assumption.
    """
    values = _checked_inputs(inputs, ("A", "B", "Cin"), check_scope)
    if check_scope:
        _require_in_scope(values)
    output_f_value = _compute_output_f(values["A"], values["B"], values["Cin"])
    return output_f_value


def evaluate(inputs: Mapping[str, bool], *, check_scope: bool = True) -> Dict[str, bool]:
    """Evaluate every output (declared order); each output is computed once.

    Required inputs: 'A', 'B', 'Cin'.
    Raises InputError for missing, undeclared, or non-bool inputs, and OutOfScopeError
    when check_scope is True and the inputs violate an assumption.
    """
    values = _checked_inputs(inputs, ("A", "B", "Cin"), check_scope)
    if check_scope:
        _require_in_scope(values)
    output_f_value = _compute_output_f(values["A"], values["B"], values["Cin"])
    return {
        "f": output_f_value,
    }
PostgreSQL
-- Tangibool PostgreSQL export (tangibool.postgresql/1)
-- Target: PostgreSQL 16 or later with typed boolean inputs; tested with PostgreSQL 18.3 (PGlite 0.5.8).
-- Not a claim of compatibility with other SQL dialects.
-- Model: not stated
-- Source revision: reference
-- Interpretation status: not stated
-- Exporter: 1.0.0 (engine 1.0.0; semantics tangibool-semantics/1)
-- Logic digest: 11c1109a9bff240df1857b52b71474b4908db824f8f3f9a0373b88b059d010b6
-- Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78
-- Mode: decision
--
-- Read-only: this file contains only WITH / VALUES / SELECT statements. No DDL, DML,
-- procedures, credentials, network access, or database changes. The expressions are pure
-- Boolean expressions, so their result does not depend on SQL evaluation order.
--
-- NON-NULL INPUT PRECONDITION: NULL is not a truth value of this rule. Every fragment below
-- is defined only when every input column it reads is a non-NULL boolean. The guard template
-- (section 2) marks any NULL input as 'invalid_input' and any row that violates the
-- assumptions as 'out_of_scope', and fills output columns only for 'ok' rows; a NULL in an
-- output column of another row is an envelope marker, not a third truth value. Never wrap
-- the fragments in COALESCE(..., FALSE) or otherwise choose a meaning for unknown inputs.
-- This evaluates the supplied model; it does not show that the model is a complete, legal,
-- or safe statement of a real-world rule.
--
-- Input columns (stable ID: name -> column):
--   v_0295965d44fd: A -> "in_A"
--   v_1b5bf3b38ee6: B -> "in_B"
--   v_d85e4452d9c6: Cin -> "in_Cin"
-- Output columns:
--   f_8769ad1f6fc1: f -> "out_f"
-- Assumptions (scope K; exported separately and never folded into an output):
--   none; every complete input row is in scope.

-- ----------------------------------------------------------------------------------------------
-- 1. Expression fragments (parenthesised; non-NULL boolean inputs required)
-- ----------------------------------------------------------------------------------------------
--
-- [out_f] output f (stable ID f_8769ad1f6fc1)
--   f := (A AND B) OR (Cin AND (A XOR B))
--   PRECONDITION: "in_A", "in_B", "in_Cin" are non-NULL booleans.
--   (("in_A" AND "in_B") OR ("in_Cin" AND ("in_A" <> "in_B")))
--

-- ----------------------------------------------------------------------------------------------
-- 2. Guard template (read-only SELECT over an inputs list)
-- ----------------------------------------------------------------------------------------------
-- Replace the example rows between the markers with your own rows, or replace the inputs
-- CTE with a SELECT that provides the boolean columns listed in the header. status is
-- 'invalid_input' when any input is NULL, 'out_of_scope' when the assumptions are false, and
-- 'ok' otherwise; output columns are filled only for 'ok' rows (NULL elsewhere is an
-- envelope marker). Assumption columns are shown for rows with complete inputs.
WITH inputs ("row_id", "in_A", "in_B", "in_Cin") AS (
  -- tangibool:example-rows:begin
  VALUES
    (1, FALSE, FALSE, FALSE),
    (2, FALSE, FALSE, TRUE),
    (3, FALSE, TRUE, FALSE),
    (4, FALSE, TRUE, TRUE),
    (5, TRUE, FALSE, FALSE),
    (6, TRUE, FALSE, TRUE),
    (7, TRUE, TRUE, FALSE),
    (8, TRUE, TRUE, TRUE),
    (9, NULL::boolean, FALSE, FALSE)
  -- tangibool:example-rows:end
),
checked AS (
  SELECT
    inputs.*,
    CASE
      WHEN "in_A" IS NULL OR "in_B" IS NULL OR "in_Cin" IS NULL THEN 'invalid_input'
      ELSE 'ok'
    END AS "status"
  FROM inputs
)
SELECT
  "row_id",
  "in_A",
  "in_B",
  "in_Cin",
  "status",
  CASE WHEN "status" = 'ok' THEN (("in_A" AND "in_B") OR ("in_Cin" AND ("in_A" <> "in_B"))) END AS "out_f"
FROM checked
ORDER BY "row_id";
SMT-LIB
; Tangibool SMT-LIB export (tangibool.smtlib/1)
; Profile: SMT-LIB 2.6 Boolean subset (QF_UF): Bool constants, define-fun, let, push/pop, assert, check-sat, echo.
; Tested with Z3 5.1.0 (z3-solver 5.2.0, WebAssembly build).
; Model: not stated
; Source revision: reference
; Interpretation status: not stated
; Exporter: 1.0.0 (engine 1.0.0; semantics tangibool-semantics/1)
; Logic digest: 11c1109a9bff240df1857b52b71474b4908db824f8f3f9a0373b88b059d010b6
; Assumptions digest: d58ee1ad38e23e5093e4baa1047b5ae70d6972e08f555e34ac3fa16df63c4a78
; Mode: decision
;
; Reading results: each query block states what sat and unsat mean for its question. A sat
; answer comes with a witness or counterexample (ask for it with (get-model) after sat only);
; unsat settles that scoped query and is solver-checked, not an independently checked proof
; certificate; unknown settles nothing. Blocks are scoped with push/pop, so assertions never
; accumulate across questions. This checks the supplied model, not whether it is a complete,
; legal, or safe statement of a real-world rule.
;
; Symbols (stable ID: name -> symbol):
;   v_0295965d44fd: A -> in_A
;   v_1b5bf3b38ee6: B -> in_B
;   v_d85e4452d9c6: Cin -> in_Cin
;   f_8769ad1f6fc1: f -> out_f

(set-option :produce-models true)
(set-info :smt-lib-version 2.6)
(set-logic QF_UF)

; ---- Inputs (declared order)
(declare-const in_A Bool) ; A
(declare-const in_B Bool) ; B
(declare-const in_Cin Bool) ; Cin

; ---- Outputs (dependencies first)
; output f (stable ID f_8769ad1f6fc1): (A AND B) OR (Cin AND (A XOR B))
(define-fun out_f () Bool (or (and in_A in_B) (and in_Cin (xor in_A in_B))))

; ---- Assumptions (the scope K; never folded into an output)
; K: conjunction of the enabled, confirmed assumptions (true when there are none)
(define-fun K () Bool true)

; ---- Definitions only: nothing is asserted and no check is run.
; Add (assert ...) and (check-sat) inside (push 1) ... (pop 1) to ask a question.
LaTeX
f = \left(A \cdot B\right) + \left(\mathit{Cin} \cdot \left(A \oplus B\right)\right)

Questions

Can it go the other way, from a circuit to an expression?

Not on this page: the tool takes an expression. The app's canvas builds the expression from gates you draw, which is the reverse direction.

Why are implication and biconditional drawn as gates?

The engine draws every operator it knows as a node so the diagram matches the expression one to one. Implication is drawn as its own node labelled with the arrow; the NAND-only tool shows how it decomposes into basic gates.

Related

Tools

Practice

Tools

Generated from the Tangibool engine, semantics tangibool-semantics/1, engine 1.0.0, build . Every table, map, simplification and verdict on these pages was computed by the Tangibool engine when the site was built, and every claim was re-checked by the same exact checker the app uses. Limits are stated where they apply. © 2026 Foreranger LTD.