Source: https://guthlabs.ai/docs/instruments/transformer-turns-ratio-sizing-calculator/implementation/

instrument implementation / implementation-contract

# Transformer Turns Ratio & Sizing Calculator implementation

A source-bound implementation contract for Transformer Turns Ratio & Sizing 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**: t4-054

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-turn secondary input produces an undefined ratio and must be rejected. Signed-voltage inputs also expose an unresolved polarity/sign convention: signed and magnitude interpretations produce different ratio and current signs.

## 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": {
    "V1_V": 120,
    "V2_V": 12,
    "load_current_A": 5
  },
  "expected_outputs": {
    "ratio_a": 10,
    "secondary_voltage_V": 12,
    "secondary_current_A": 5,
    "primary_current_A": 0.5,
    "required_VA": 60
  },
  "working": "a=V1/V2=120/12=10. I1=I2/a=5/10=0.5 A. VA=V2·I2=12·5=60 VA."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/transformer-turns-ratio-sizing-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/transformer-turns-ratio-sizing-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/transformer-turns-ratio-sizing-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`