BJT Amplifier Gain Estimator (Common-Emitter) 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

t5-171

Effect

Computation or source lookup only

Input and validation requirements

The valid-looking boundary input IC=0 makes re=26 mV/IE divide by zero, causing Av and Zin to be undefined. The estimator must reject zero collector/emitter current instead of forcing numeric results.

Required corrections

[
  {
    "vector": 3,
    "field": "Zin",
    "wrong": 33015.873,
    "correct": 32974.001,
    "cause": "final reciprocal of her own correct conductance sum divided slightly wrong"
  }
]

Inspectable interface fixture

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

{
  "inputs": {
    "IC": "1.000 mA",
    "RC": "4700 Ω",
    "R1": "100000 Ω",
    "R2": "20000 Ω",
    "β": 100
  },
  "expected_outputs": {
    "Av": -182.576923,
    "Zin": "2229.846 Ω",
    "Zout": "4700 Ω"
  },
  "working": "IE=IC(1+1/β)=0.001(1+1/100)=0.00101 A. re=0.026/0.00101=25.742574 Ω. Av=−4700/25.742574=−182.576923. βre=100×25.742574=2574.2574 Ω. Zin=1/(1/100000+1/20000+1/2574.2574)=1/(0.00001+0.00005+0.000388461538)=1/0.000448461538=2229.846 Ω. Zout=RC=4700 Ω."
}

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