electrical.timer_555

Three distinct suites: educational examples on the calculator page, this legacy regression count (30/30 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 1.2.0 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 2026-10-28.meta-metrics-v2. Calculation version 1.2.0. CVP 1.0.0-proposed. 2/2 golden · 6/6 CVP boundary · 5/5 invalid · 20/20 property · 2/2 metamorphic · 2/2 cross-interface · 10/10 CVP contract. digest 037b29b457ca. Ideal NE555 astable/monostable timing vs independent O2 (same V8, ≤2 ULP). Not a claim of assembled-circuit frequency or pulse accuracy.

• Golden (oracle-backed) 2 / 2
• CVP boundary 6 / 6
• Invalid input 5 / 5
• Property 20 / 20
• Metamorphic 2 / 2
• Cross-interface 2 / 2
• CVP contract 10 / 10
• Interfaces PASS · UI (SSR) / REST / MCP
• Interface claim ui-ssr is query-result HTML, not a live browser session.
• Verified scope ideal NE555 timing calculation
• Assurance Engineering

• contract page version PASS
• contract capability version PASS
• contract input schema version PASS
• contract output schema version PASS
• evidence version matches manifest PASS
• schema output required declared PASS
• schema valid input executes PASS
• engine success output validates schema PASS
• schema rejects incomplete input PASS
• rest success payload validates schema PASS

Fingerprint sha256:1a51575bf7b0ceba9f65415e320250f555e4e84e56bcee0c6e35e9c84dc080c5

Input schema sha256:28c7a7495fb90986ab08fc38e0861f68022f58ce939c9a2f4d7325767a94301b · Output schema sha256:fbf0aeb7cd3b62a5f0749610a7a4c6a0bec3152dee5773f0e965d687b4a4d633 · 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.

Tool

timer-555

Engine

timer-555

Engine build

2026-09-10

Evidence core

2026-09-09T14:46:37.636Z

Rendered

2026-11-10T05:18:41.767Z

Last reviewed

2026-08-13

Assumptions

• Classic NE555 ideal timing thresholds (≈⅓ / ⅔ VCC)
• Standard astable topology without duty-cycle diode
• Astable timing uses ln(2); TI 0.693/1.44 are rounded aliases

Limitations

• Classic NE555 ideal timing — astable uses ln(2) canonical model; TI 0.693/1.44 are rounded aliases
• Device families differ in timing accuracy, leakage, output/discharge characteristics and usable frequency range; verify the selected device datasheet
• Standard astable wiring always yields duty > 50%; diode-across-R2 <50% trick is not modeled
• f > 100 kHz → NE555_HIGH_FREQUENCY warning (NE555 distortion guidance)
• Monostable pulse_width < ~10 µs → MONOSTABLE_SHORT_PULSE warning
• mode-discriminated oneOf: astable requires R1,R2,C; monostable requires R,C
• Frozen at calculation_version 1.2.0 for forward timing — Designer / E-series / tolerance are separate surfaces