Source: https://guthlabs.ai/docs/instruments/thermal-johnson-nyquist-noise-calculator/implementation/

instrument implementation / implementation-contract

# Thermal (Johnson-Nyquist) Noise Calculator implementation

A source-bound implementation contract for Thermal (Johnson-Nyquist) Noise Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_WITH_ERRATA**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-with-binding-errata

**Evidence ID**: t5-207

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification does not state the current-noise formula or input units explicitly. R=0 produces an undefined current result, negative temperature produces a non-real square-root argument, and an unlabelled temperature such as 25 is ambiguous between kelvin and Celsius.

## Required corrections

````
[
  {
    "vector": "all(1-3)",
    "field": "Vn_rms_V / In_rms_A",
    "wrong": "v1 1.287e-8, v2 5.66e-7, v3 4.07e-9 (and In)",
    "correct": "v1 4.070e-7, v2 4.002e-6, v3 4.071e-7 — Vn=√(4kTRB)",
    "cause": "systematic: R omitted under the square root (her values = √(4kTB) exactly); caught only by the floor-audit of my own gate"
  }
]
````

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "R_ohm": 1000,
    "temperature_K": 300,
    "bandwidth_Hz": 10000
  },
  "expected_outputs": {
    "Vn_rms_V": 1.2871592e-8,
    "In_rms_A": 1.2871592e-11
  },
  "working": "4kTRΔf = 4×(1.380649e-23)×1000×300×10000 = 1.6567788e-16 V^2. Vn = sqrt(1.6567788e-16) = 1.2871592e-8 V rms. In = Vn/R = (1.2871592e-8)/1000 = 1.2871592e-11 A rms."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/thermal-johnson-nyquist-noise-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/thermal-johnson-nyquist-noise-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/thermal-johnson-nyquist-noise-calculator/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-tranche5/tranche5-results.json`

- `tranche errata record`