Source: https://guthlabs.ai/docs/instruments/pcb-via-current-capacity-calculator/implementation/

instrument implementation / implementation-contract

# PCB Via Current Capacity Calculator implementation

A source-bound implementation contract for PCB Via Current Capacity Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**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-clean

**Evidence ID**: t4-222

**Effect**: Computation or source lookup only

## Input and validation requirements

The model has an undefined real-valued result for negative delta_T, and the supplied specification omits the IPC constant selection, dimensional units, and any thermal-environment branch input. Consequently, identical numeric entries can produce materially different results or NaN unless the calculator validates and disambiguates them.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

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

````
{
  "inputs": {
    "via_diameter_mil": 20,
    "plating_thickness_mil": 1,
    "delta_T_C": 10,
    "via_count": 1
  },
  "expected_outputs": {
    "max_current_per_via_A": 1.378,
    "max_current_array_A": 1.378
  },
  "working": "A = π × t × (D + t) = 3.14159265 × 1 × (20 + 1) = 65.9734 mil². ΔT^0.44 = 10^0.44 = 2.75423. A^0.725 = 65.9734^0.725 ≈ 20.8469. I_via = 0.024 × 2.75423 × 20.8469 = 1.378 A. I_array = 1 × 1.378 = 1.378 A."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/pcb-via-current-capacity-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/pcb-via-current-capacity-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/pcb-via-current-capacity-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-tranche4/tranche4-results.json`