Schmitt Trigger Threshold 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-with-binding-errata

Evidence ID

t5-189

Effect

Computation or source lookup only

Input and validation requirements

The denominator can be forced to zero with R1+R2=0, producing an undefined threshold that must be rejected. In addition, the specification provides only one threshold formula and does not explicitly define how VTH_plus and VTH_minus, reference polarity, or signed hysteresis are derived.

Required corrections

[
  {
    "vector": 2,
    "field": "VTH_plus/minus/hysteresis",
    "wrong": "±9.4737 / 18.947",
    "correct": "±9.8947 / 19.789",
    "cause": "outputs contradict her own working which computes (and self-corrects to) 9.8947"
  }
]

Inspectable interface fixture

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

{
  "inputs": {
    "Vsat": 5,
    "R1": 10000,
    "R2": 20000,
    "reference_config": "zero reference; symmetric rails; R1 and R2 in ohms"
  },
  "expected_outputs": {
    "VTH_plus": 1.6666666667,
    "VTH_minus": -1.6666666667,
    "hysteresis": 3.3333333333
  },
  "working": "R1+R2=10000+20000=30000 ohms. VTH magnitude=5×10000/30000=50000/30000=1.6666666667 V. VTH+=+1.6666666667 V. VTH−=−1.6666666667 V. Hysteresis=VTH+−VTH−=1.6666666667−(−1.6666666667)=3.3333333333 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-tranche5/tranche5-results.json
• tranche errata record