Source: https://guthlabs.ai/docs/instruments/resistor-color-code-decoder-encoder/mechanism/

instrument mechanism / verified-clean

# Resistor Color Code Decoder/Encoder mechanism

The inspectable method record for Resistor Color Code Decoder/Encoder, kept separate from implementation and qualification.

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

## Model scope

The core color-code lookup and resistance calculation are standard and correct for the tested 4-, 5-, and 6-band cases. Before release, define supported color-code conventions, mandatory encoder parameters, unit handling, invalid-input behavior, canonical rounding/E-series policy, and whether the product claims to encode 6-band temperature coefficients. The empty honest_label should be completed to state that reverse encoding may round or reject values and that any future camera recognition is not part of version 1.

- The stated lookup-table method is standard, but the specification does not explicitly define the digit count: 4-band uses two significant digits, while 5-band and 6-band use three significant digits.

- For 6-band codes, the sixth band is a temperature-coefficient lookup and must be reported separately; it does not change the nominal resistance.

- Reverse encoding is underspecified: the required band count, tolerance, temperature coefficient, rounding policy, and preferred representation for values not exactly representable by a valid color code are not defined.

- The implementation must reject invalid band sequences, including unsupported colors, missing tolerance bands, negative or zero resistance inputs where not explicitly supported, and noncanonical significant-digit requests.

## Units and conventions

- Decoded resistance is reported in ohms unless a display-unit option is explicitly defined.

- Tolerance is expressed as percent and applies symmetrically to the nominal resistance: lower=R×(1−t/100), upper=R×(1+t/100).

- Encoder input units must be explicit; vector 4 uses kilohms and converts by 1 kΩ=1000 Ω before selecting bands.

- Temperature coefficient is expressed in ppm/K; numerically, ppm/K and ppm/°C increments are equivalent for a temperature difference.

## Inspectable vector

One of 4 source-bound review vectors:

````
{
  "inputs": {
    "mode": "decode",
    "band_colors": [
      "brown",
      "black",
      "red",
      "gold"
    ]
  },
  "expected_outputs": {
    "nominal_resistance_ohms": 1000,
    "tolerance_percent": 5,
    "resistance_range_ohms": {
      "min": 950,
      "max": 1050
    }
  },
  "reference_data": {
    "digit_bands": [
      {
        "color": "brown",
        "digit": 1,
        "source_convention": "IEC 60062 / widely tabulated standard value"
      },
      {
        "color": "black",
        "digit": 0,
        "source_convention": "IEC 60062 / widely tabulated standard value"
      }
    ],
    "multiplier_band": {
      "color": "red",
      "factor": 100,
      "source_convention": "IEC 60062 / widely tabulated standard value"
    },
    "tolerance_band": {
      "color": "gold",
      "tolerance_percent": 5,
      "source_convention": "IEC 60062 / widely tabulated standard value"
    },
    "table_entry": {
      "color_code": "brown-black-red-gold",
      "meaning": "1 kΩ ±5%",
      "source_convention": "IEC 60062 / widely tabulated standard value"
    }
  },
  "working": "4-band nominal value = (brown digit 1×10 + black digit 0)×red multiplier 100 = 10×100 = 1000 Ω. Tolerance = 1000×5/100 = 50 Ω. Minimum = 1000−50 = 950 Ω. Maximum = 1000+50 = 1050 Ω."
}
````

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

The extreme-value encoder input lies outside the supported EIA multiplier range and must be rejected explicitly. The decoder also has a convention hazard if band direction or the metallic tolerance band is not identified, and the exact-zero code should be flagged as a zero-ohm jumper rather than treated as an ordinary resistor.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/resistor-color-code-decoder-encoder/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/resistor-color-code-decoder-encoder/implementation/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/resistor-color-code-decoder-encoder/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche7/tranche7-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`