Source: https://guthlabs.ai/docs/instruments/capacitor-code-decoder/

instrument / verified-clean

# Capacitor Code Decoder

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

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/capacitor-code-decoder/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/capacitor-code-decoder/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/capacitor-code-decoder/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/capacitor-code-decoder/qualification/>)

## 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**: t7-041

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The capacitance arithmetic is standard and the four worked vectors are valid under the explicitly stated convention. The instrument cannot receive a PASS until it specifies the supported marking syntax and authoritative voltage-code table, and separates tolerance decoding from voltage decoding. Honest labeling should say that decoded values are nominal markings and that voltage and tolerance suffixes are manufacturer- and standard-dependent.

### Formula and scope findings

- The 3-digit capacitance rule is correct for the common EIA capacitor convention: first two digits are significant figures, the third digit is the base-10 multiplier, and the result is in pF.

- The statement 'letter = tolerance' is incomplete: tolerance letters are convention-dependent, and a letter may instead be a voltage, temperature-characteristic, or manufacturer-specific code.

- The specification claims voltage-code lookup but does not define the code position, marking syntax, or applicable standard. A voltage letter cannot be decoded reliably from an isolated printed code.

- The specification does not state handling for decimal-R codes such as 4R7, four-digit codes, two-digit codes, leading-zero codes, manufacturer-specific SMD markings, or invalid multiplier digits.

- THT and SMD capacitor marking conventions are not interchangeable; the supported package and marking standard must be explicitly selected.

### Unit assumptions

- For the tested convention, the decoded capacitance is in pF.

- 1 nF = 1,000 pF and 1 µF = 1,000,000 pF.

- Tolerance letters use the IEC 60062:2016 convention: J = ±5%, K = ±10%, and M = ±20%.

- Voltage letters use the EIA-198 voltage-code convention only when supplied as a separate, explicitly identified voltage code: A = 1.0 V, K = 10 V, M = 20 V, and R = 50 V.

- The test inputs use a separated voltage_code field because concatenated printed-code syntax is unspecified by the instrument.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The specification does not define handling for the zero result in 000J and does not supply the voltage-rating lookup table, so voltage output cannot be determined for any vector. Code-letter interpretation is also table-dependent.

## 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": {
    "printed_code": "104J",
    "voltage_code": "K",
    "marking_convention": "3-digit capacitance + IEC tolerance suffix + separate EIA-198 voltage code"
  },
  "expected_outputs": {
    "capacitance_pF": 100000,
    "capacitance_nF": 100,
    "capacitance_uF": 0.1,
    "tolerance": "±5%",
    "voltage_rating_V": 10
  },
  "reference_data": {
    "capacitance_code_rows": [
      {
        "code": "104",
        "capacitance_pF": 100000
      }
    ],
    "tolerance_code_rows": [
      {
        "code": "J",
        "tolerance": "±5%"
      }
    ],
    "voltage_code_rows": [
      {
        "code": "K",
        "voltage_V": 10
      }
    ],
    "source_convention": "EIA 3-digit capacitor marking convention; tolerance and voltage values from IEC 60062:2016 and EIA-198 voltage-code convention; widely tabulated standard values"
  },
  "working": "First two digits: 10. Multiplier: 10^4. Capacitance = 10 × 10^4 pF = 100,000 pF. Convert: 100,000 pF ÷ 1,000 = 100 nF; 100,000 pF ÷ 1,000,000 = 0.1 µF. J = ±5%. EIA-198 K = 10 V."
}
````

## 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`