Public evidence

electrical.watts_to_volts

Machine-checked verification for calculation version 1.3.1 · tier engine_tested

Open calculator API Capability Download JSON CVP Manifest MCP Review policy

CVP status

V from P and I, or P and R; reverse P = V·I·PF

Declared partition coverage: PASS · 4/4 declared partitions (w-v-a, w-v-r, v-w, invalid-domain)
Versions: Calculation 1.3.1 · CVP protocol 1.0.0-proposed
CVP identity: 0/0 property · digest 21e542929dd0

Verification

Legacy regression suite: 13/13 calculation tests · Production surface contract 4/4

Three distinct suites: educational examples on the calculator page, this legacy regression count (13/13 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 1.3.1 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Calculation version 1.3.1. CVP 1.0.0-proposed. 3/3 golden · 1/1 CVP boundary · 1/1 invalid · 1/1 cross-interface · 4/4 CVP contract. digest 21e542929dd0.

Golden (oracle-backed) 3 / 3
CVP boundary 1 / 1
Invalid input 1 / 1
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 output required declared PASS
schema rejects incomplete input PASS
rest success payload validates schema PASS

Fingerprint sha256:7ed8b340fe91a2cfbe681b97756c3c945dd364d07749b3fd19ef79a76b536c50

Input schema sha256:99ac5e80af45491165a11fc9e03cbf553b639dee45bc84ec7b63327a26602f8b · Output schema sha256:6f0594702054be60fbdf476ae690caebfa74cac4dba5822b2533109281c7f4a5 · 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: watts-to-volts
Engine: watts-to-volts
Engine build: 2026-09-24
Evidence core: 2026-09-24T09:04:14.075Z
Rendered: 2026-09-24T09:22:02.325Z
Last reviewed: —

Assumptions

RMS quantities for AC
Balanced three-phase when √3 selected
Ohms path assumes real resistive (or |Z| for RF magnitude)

Limitations

RMS quantities for AC
Balanced three-phase when phase is three
Ohms path is resistive magnitude, V = √(P·R)

Sources

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

Watt’s law / power identity — Real power P = V × I × PF (1φ); P = √3 × V × I × PF (3φ L-L)
Supports: V = P/(I·PF); P = V·I·PF; 3φ with √3
Resistive power identity — P = V²/R ⇒ V = √(P·R)
Supports: W → V (ohms) / RF |Z| magnitude path
IEC 60050 — International Electrotechnical Vocabulary — Active power (IEV 131-11-42)
Supports: P is active power; unit watt (W). Watts-path voltage uses P, not apparent power S.
IEC 60050 — International Electrotechnical Vocabulary — Power factor (IEV 131-11-46)
Supports: λ = |P| / S; AC watts path V = P / (I·λ) (1φ) or V = P / (√3·I·λ) (3φ L-L)
IEEE Std 1459-2025 — Power factor in AC real-power calculations · 2025-05-16 · errata checked
Supports: PF scaling on amps and reverse watts paths
BIPM SI Brochure (9th edition, version 4.01) — SI units for ampere, volt, ohm, and watt · 2026-06 · DOI
Supports: DC V = P/I; V = √(P·R) from P = V²/R
NIST Guide to the SI (SP 811) — Volt, ampere, ohm, watt
Supports: SI unit relationships for V, A, Ω, W

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
`dc-240-2`	golden	pass	Expected 120 · Actual 120
`dc-20-4`	golden	pass	Expected 5 · Actual 5
`1phi-1300`	golden	pass	Expected 120.37 · Actual 120.37037037037037
`3phi-1000-10-0.8`	golden	pass	Expected 72.17 · Actual 72.16878364870323
`ohms-40-10`	golden	pass	Expected 20 · Actual 20
`ohms-0.1-50`	golden	pass	Expected 2.236 · Actual 2.23606797749979
`v-to-w`	golden	pass	Expected 240 · Actual 240
`linear-2x-P`	golden	pass	Expected 240 · Actual 240
`inverse-half-I`	golden	pass	Expected 240 · Actual 240
`soft-zero-I`	golden	pass	Expected 0 · Actual 0
`soft-zero-P`	golden	pass	Expected 0 · Actual 0
`soft-pf-le-0-as-1`	golden	pass	Expected 120 · Actual 120
`soft-negative-sqrt`	golden	pass	Expected 0 · Actual 0