Voltage Regulator (Linear) Resistor/Output Calculator implementation

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

t4-268

Effect

Computation or source lookup only

Input and validation requirements

• Division by zero occurs when calculating R2 if Vref/R1 + Iadj = 0; this can occur with invalid R1, zero Vref, or negative/unphysical Iadj.
• Division by zero occurs when calculating R1 if Vout - Vref - Iadj·R2 = 0.
• Calculated resistor values can be zero or negative; the calculator must reject nonpositive resistor values for a physical design, except that R2 = 0 is mathematically valid as a boundary test case.
• R1 = 0 is invalid because the forward formula contains R2/R1.
• Inputs must reject negative resistance, negative Vref where inappropriate, and inconsistent target values that require a negative resistor.
• The result may violate the regulator's minimum-load-current requirement, maximum output-current rating, power dissipation, or dropout-voltage requirement.
• Using milliamps or microamps as though they were amperes causes a factor-of-1000 or factor-of-1000000 error in the Iadj term.
• A fixed minimum-load threshold cannot be reported honestly without specifying the regulator part number or an explicit threshold.

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": {
    "Vref_V": 1.25,
    "R1_ohm": 240,
    "R2_ohm": 720,
    "Iadj_A": 0.00005
  },
  "expected_outputs": {
    "Vout_V": 5.036
  },
  "working": "R2/R1 = 720/240 = 3. 1 + R2/R1 = 4. Vref·(1 + R2/R1) = 1.25·4 = 5.000 V. Iadj·R2 = 0.00005·720 = 0.036 V. Vout = 5.000 + 0.036 = 5.036 V."
}

Other records

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