Public evidence

electrical.watts_to_joules

Machine-checked verification for calculation version 1.2.1 · tier engine_tested

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Verification

12/12 calculation tests · Production surface contract 4/4

Golden tests 12 / 12
Boundary tests 0 / 0
Property tests 0 / 0
Production surface contract 4 / 4
Engine tested Yes
Source checked Yes
Artifact integrity PASS
Production attestation Embedded snapshot: STALE · Last attested schema matched 1.2.1 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 164 CURRENT) @ 2026-09-16T06:44:24.909Z
Semantic contract PASS
Evidence attested at 2026-09-16T06:44:24.203Z
Last production check 2026-09-16T06:44:24.203Z
Public / cache PASS
Origin PASS
Supplemental domain review Not performed
Named expert review Not performed

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

Fingerprint sha256:216862ae51ca8c327d057d7e892ad7cd4fa43b9fe85beeffe34d7955d68c9d9f

Input schema sha256:da3d1b267a74f132e3257403f322dc1bb601395a234ecd1fef9d7536f9f91843 · Output schema sha256:72d67f9137352c1ceafea373b07c571e8e34cdede5a47e2c582c589dbb506844 · 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-joules
Engine: product
Engine build: 2026-09-15
Evidence core: 2026-09-15T06:31:46.555Z
Rendered: 2026-09-16T22:03:43.708Z
Last reviewed: —

Assumptions

Constant average power over the interval

Limitations

Cannot convert watts to joules without a duration
Shares the product helper with V→J; contracts are distinct (t vs Q)

Sources

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

SI definition of the watt — 1 W = 1 J/s
Supports: E = P × t; P = E / t
NIST Guide to the SI (SP 811) — Joule and watt as coherent SI units
Supports: Energy–power–time relationships; Wh/kWh note
IEC 60050 — International Electrotechnical Vocabulary — Active power (IEV 131-11-42)
Supports: P is active power; unit watt (W)
IEC 60050 — International Electrotechnical Vocabulary — Active energy (IEV 131-11-57)
Supports: Active energy W = ∫p dt; coherent SI unit joule (J). Distinguishes energy from power
BIPM SI Brochure (9th edition, version 4.01) — Watt as joule per second · 2026-06 · DOI
Supports: 1 W = 1 J/s; E = P × t

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`100W-60s`	golden	pass	Expected 6000 · Actual 6000
`50W-25s`	golden	pass	Expected 1250 · Actual 1250
`2W-1h`	golden	pass	Expected 7200 · Actual 7200
`j-to-w`	golden	pass	Expected 100 · Actual 100
`100W-1min`	golden	pass	Expected 6000 · Actual 6000
`j-w-h`	golden	pass	Expected 2 · Actual 2
`linear-2x-P`	golden	pass	Expected 12000 · Actual 12000
`linear-2x-t`	golden	pass	Expected 12000 · Actual 12000
`soft-zero-P`	golden	pass	Expected 0 · Actual 0
`soft-zero-t`	golden	pass	Expected 0 · Actual 0
`soft-zero-t-reverse`	golden	pass	Expected 0 · Actual 0
`soft-zero-E-reverse`	golden	pass	Expected 0 · Actual 0