Standard Value Finder (E-series)

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Electrical & Electronics Engineering — Circuits, Power Systems, Electronics Lab

Tranche

tranche-7

Evidence ID

t7-051

Ledger rows

1

No ledger note is attached.

Review findings

The lookup concept is standard and the four vectors are correct under absolute-distance selection with IEC 60063 preferred values. Verdict remains NEEDS_REVIEW because the specification does not define the distance metric, tolerance behavior, decade scaling, invalid-input policy, or tie rule. The honest label should state that this is a nominal E-series preferred-value finder, not a component availability, tolerance, rating, or measured-value verifier.

Formula and scope findings

• The E-series lookup-table method is standard, but 'nearest' is undefined: absolute numerical distance, logarithmic distance, or another metric could produce different results.
• The tolerance input is unused by the stated algorithm. The specification must define whether tolerance filters compatible E-series values, only reports the tolerance band, or is merely informational.
• The decade-scaling rule is not explicitly stated. Standard E-series values require multiplying a normalized table entry by 10^n.
• E-series entries are standardized rounded preferred numbers; regenerating them from an ideal geometric formula can disagree with the IEC table. The implementation should use the IEC table as authoritative.
• Tie handling is unspecified when a target is exactly midway between two preferred values.
• The specification does not state whether zero, negative values, or non-finite values are rejected. Capacitor and resistor practical limits, voltage ratings, and power ratings are also outside this nominal-value lookup.

Unit assumptions

• All target values in these vectors are interpreted as ohms because target_unit is explicitly supplied as ohm.
• The selected nearest value uses absolute numerical distance in ohms.
• Normalized E-series entries are multiplied by the stated decade multiplier, which must be a power of ten.
• Tolerance is expressed in percent and is not used to select the nominal value in these vectors.
• The same preferred-number lookup convention is applicable to resistor or capacitor nominal values, but the result does not establish a component's voltage, power, dielectric, ESR, or physical availability.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The specification does not define behavior for zero or negative targets, has no supported decade bounds for the zero limit, and leaves the meaning of the tolerance input ambiguous. The tolerance probe can produce either no qualifying value or a 12-ohm/15-ohm tie depending on convention.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "target_value": 4700,
    "target_unit": "ohm",
    "series": "E12",
    "tolerance_percent": 5
  },
  "expected_outputs": {
    "nearest_standard_value_ohm": 4700,
    "normalized_value": 4.7,
    "decade_multiplier": 1000,
    "absolute_error_ohm": 0
  },
  "reference_data": {
    "series": "E12",
    "normalized_values": [
      4.7
    ],
    "decade_multiplier": 1000,
    "source_convention": "IEC 60063 preferred-number series; widely tabulated standard value"
  },
  "working": "1. The E12 table contains normalized value 4.7.\n2. Apply the decade multiplier: 4.7 × 1000 = 4700 ohm.\n3. Compare with the target: |4700 - 4700| = 0 ohm.\n4. Therefore the nearest nominal is 4700 ohm (4.7 kohm). The 5% tolerance does not alter nominal selection under the stated assumption."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche7/tranche7-results.json
• BOUNDARY_HAZARD_CATALOG.json