Source: https://guthlabs.ai/docs/instruments/electric-field-from-point-charge-s-calculator/implementation/

instrument implementation / implementation-contract

# Electric Field from Point Charge(s) Calculator implementation

A source-bound implementation contract for Electric Field from Point Charge(s) 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**: t5-174

**Effect**: Computation or source lookup only

## Input and validation requirements

A nonzero point charge at the field point makes r² = 0, so the electric field is undefined. The calculator must reject coincident charge and field-point inputs rather than produce a numeric result.

## 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": {
    "charges": [
      {
        "q": "2 μC",
        "position_m": [
          0,
          0
        ]
      }
    ],
    "field_point_m": [
      3,
      4
    ],
    "k_N_m2_per_C2": 8987550000
  },
  "expected_outputs": {
    "E_vector_N_per_C": [
      431.4024,
      575.2032
    ],
    "E_magnitude_N_per_C": 719.004,
    "direction_unit_vector": [
      0.6,
      0.8
    ]
  },
  "working": "Displacement=(3−0,4−0)=(3,4) m. r=√(3²+4²)=5 m. q=2 μC=2×10⁻⁶ C. E=kq/r²=(8.98755×10⁹)(2×10⁻⁶)/25=17,975.1/25=719.004 N/C. Direction=(3/5,4/5)=(0.6,0.8). Vector E=719.004(0.6,0.8)=(431.4024,575.2032) N/C."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/electric-field-from-point-charge-s-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/electric-field-from-point-charge-s-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/electric-field-from-point-charge-s-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`