Public evidence

electrical.current_divider

Machine-checked verification for calculation version 1.0.2 · tier internally_reviewed

Open calculator API Capability Download JSON CVP Manifest MCP Review policy

CVP: CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· Exactly two ideal resistive parallel branches; no additional branch or load. Currents are non-negative magnitudes. · Protocol · Schema · Production report

Declared partition coverage: PASS · 8/8 declared partitions (from-It-R, from-I1-R, from-I2-R, from-It-I1-R1, from-It-I1-R2, underdetermined-currents, inverse-endpoint, invalid-domain)
Versions: Calculation 1.0.2 · CVP protocol 1.0.0-proposed · Evidence 2026-09-14.inverse-endpoints-schema
Verification revision: 2026-09-14.inverse-endpoints-schema · 2/2 property · digest 5836a820dfe6

Verification

Legacy regression suite: 23/23 calculation tests · Production surface contract 4/4

Three distinct suites: educational examples on the calculator page, this legacy regression count (23/23 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.0.2 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-14.inverse-endpoints-schema. Calculation version 1.0.2. CVP 1.0.0-proposed. 5/5 golden · 14/14 CVP boundary · 20/20 invalid · 2/2 property · 3/3 metamorphic · 1/1 cross-interface · 4/4 CVP contract. digest 5836a820dfe6.

Golden (oracle-backed) 5 / 5
CVP boundary 14 / 14
Invalid input 20 / 20
Property 2 / 2
Metamorphic 3 / 3
Cross-interface 1 / 1
CVP contract 4 / 4
Interfaces PASS · UI (SSR) / REST / MCP
Interface claim ui-ssr is query-result HTML, not a live browser session.
Assurance Engineering

release artifacts aligned PASS
schema valid input executes PASS
engine success output validates schema PASS
schema rejects incomplete input PASS

Fingerprint sha256:503e9a018cc00a1ca3c8546171a4ed84c28bbf686f0cc7b955d00d3e1ca1bcdc

Input schema sha256:fd2d62434ceb76f8c2f295d990f1727eac827ffc06a620cee27bd74671500934 · Output schema sha256:38d5757df93af788f9c6c92980690a4fcf9221950a9be94f3fd32febb3ec5251 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool: current-divider
Engine: current-divider
Engine build: 2026-09-14
Evidence core: 2026-09-14T03:15:03.452Z
Rendered: 2026-09-16T22:03:43.724Z
Last reviewed: 2026-09-14

Assumptions

Exactly two ideal resistive parallel branches; no additional branch or load
DC / resistive; currents entered as non-negative magnitudes

Limitations

Exactly two ideal resistive parallel branches; no additional branch or load
Currents are non-negative magnitudes
Web UI is It+R1+R2 only
API supported combinations: It+R1+R2, R1+R2+I1, R1+R2+I2, It+I1+R1, It+I1+R2
It+I1+I2 is underdetermined → UNSUPPORTED_COMBINATION
Inverse It+I1+R1/R2 requires 0 < I1 < It for a finite R>0; I1=0 or I1=It → CURRENT_SPLIT_INVALID
It=0 and I1=0 with R1 or R2 is underdetermined → UNSUPPORTED_COMBINATION
<3 inputs → NEEDS_THREE_INPUTS

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

IEC 60050 — International Electrotechnical Vocabulary — Kirchhoff law for nodes (IEV 131-15-09)
Supports: Algebraic sum of currents at a node is zero; I1 + I2 = It for two parallel branches
IEC 60050 — International Electrotechnical Vocabulary — Resistance (IEV 131-12-04)
Supports: R = u/I on each branch; common node voltage V = I1·R1 = I2·R2
Horowitz & Hill — The Art of Electronics — 3rd ed., Cambridge University Press, 2015 — Chapter 1 Foundations, current dividers · 2015
Supports: Two-branch inverse-R current split

Methods

Algorithms this engine uses. Not external references.

Kirchhoff's current law (KCL): I1 + I2 = It
Ohm's law: V = I1·R1 = I2·R2

Legacy published checks

Golden and boundary cases from the legacy Evidence JSON. CVP property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the Manifest — including SKIP when a suite has no vectors.

ID	Kind	Status	Detail
`basic`	golden	pass	Expected I1=0.02 · I2=0.01 · V=2 · Actual It=0.03 · R1=100 · R2=200 · I1=0.02 · I2=0.01 · V=2
`needs-three`	boundary	pass	Expected NEEDS_THREE_INPUTS · Actual NEEDS_THREE_INPUTS
`zero-R`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`solve-from-I1`	golden	pass	Expected It=0.03 · I2=0.01 · Actual It=0.03 · R1=100 · R2=200 · I1=0.02 · I2=0.009999999999999998 · V=2
`solve-from-I2`	golden	pass	Expected It=0.03 · I1=0.02 · Actual It=0.03 · R1=100 · R2=200 · I1=0.019999999999999997 · I2=0.01 · V=1.9999999999999998
`solve-R2`	golden	pass	Expected R2=200 · I2=0.01 · Actual It=0.03 · R1=100 · R2=200.00000000000003 · I1=0.02 · I2=0.009999999999999998 · V=2
`solve-R1`	golden	pass	Expected R1=100 · I2=0.01 · Actual It=0.03 · R1=99.99999999999999 · R2=200 · I1=0.02 · I2=0.009999999999999998 · V=1.9999999999999998
`inverse-i1-zero-R1`	boundary	pass	Expected CURRENT_SPLIT_INVALID · Actual CURRENT_SPLIT_INVALID
`inverse-i1-eq-It-R1`	boundary	pass	Expected CURRENT_SPLIT_INVALID · Actual CURRENT_SPLIT_INVALID
`inverse-zero-It-I1-R1`	boundary	pass	Expected UNSUPPORTED_COMBINATION · Actual UNSUPPORTED_COMBINATION
`inverse-i1-zero-R2`	boundary	pass	Expected CURRENT_SPLIT_INVALID · Actual CURRENT_SPLIT_INVALID
`inverse-i1-eq-It-R2`	boundary	pass	Expected CURRENT_SPLIT_INVALID · Actual CURRENT_SPLIT_INVALID
`inverse-zero-It-I1-R2`	boundary	pass	Expected UNSUPPORTED_COMBINATION · Actual UNSUPPORTED_COMBINATION
`boundary-zero-It`	boundary	pass	Expected I1=0 · I2=0 · V=0 · Actual It=0 · R1=100 · R2=200 · I1=0 · I2=0 · V=0
`boundary-extreme-ratio`	boundary	pass	Expected I1=0.02999999997 · I2=2.999999997e-11 · Actual It=0.03 · R1=1 · R2=1000000000 · I1=0.02999999997 · I2=2.999999997e-11 · V=0.02999999997
`boundary-underdetermined`	boundary	pass	Expected UNSUPPORTED_COMBINATION · Actual UNSUPPORTED_COMBINATION
`boundary-split`	boundary	pass	Expected CURRENT_SPLIT_INVALID · Actual CURRENT_SPLIT_INVALID
`property-split`	property	pass	2:1 split
`property-linear`	property	pass	2It
`property-kcl`	property	pass	I1+I2=It
`property-ohm`	property	pass	I1 R1 = I2 R2 = V
`property-swap`	property	pass	swap R1↔R2
`property-scale`	property	pass	scale R ×10