{
  "schemaVersion": 1,
  "id": "resistive-step",
  "kind": "line",
  "model": "labWaves",
  "modelVersion": "1.2",
  "contractVersion": "2.2",
  "params": {
    "Z0": 50,
    "Rs": 50,
    "RL": 75,
    "open": false,
    "tr": 60,
    "len": 3,
    "xp": 100
  },
  "topology": "1 V ideal source, series Rs, uniform 50 Ω lossless line, resistive or ideal-open termination.",
  "planes": "Load at x=L. Observation is after the first edge has finished; source-matched case is after the return reaches the source.",
  "evidence": {
    "type": "analytical",
    "provenance": "First-principles boundary conditions, linear circuit laws or the declared teaching-loop equation; no measured or licensed data."
  },
  "checks": [
    {
      "metric": "gammaLoad",
      "expected": 0.2,
      "absoluteTolerance": 1e-10,
      "unit": "-",
      "derivation": "Open: ΓL=+1; otherwise ΓL=(RL−Z0)/(RL+Z0)."
    },
    {
      "metric": "gammaSource",
      "expected": 0.0,
      "absoluteTolerance": 1e-10,
      "unit": "-",
      "derivation": "ΓS=(Rs−Z0)/(Rs+Z0)."
    },
    {
      "metric": "launchedVoltage",
      "expected": 0.5,
      "absoluteTolerance": 1e-10,
      "unit": "V",
      "derivation": "A 1 V source launches Z0/(Rs+Z0) volts."
    },
    {
      "metric": "loadVoltage",
      "expected": 0.6,
      "absoluteTolerance": 1e-10,
      "unit": "V",
      "derivation": "Before a later nonzero return reaches the load, VL=a(1+ΓL). With source matching ΓS=0, no further return is launched."
    },
    {
      "metric": "loadCurrent",
      "expected": 0.008,
      "absoluteTolerance": 1e-10,
      "unit": "A",
      "derivation": "IL=a(1−ΓL)/Z0, positive toward the load."
    }
  ],
  "lesson": {
    "prediction": "Predict the signs of the reflected voltage and load current before opening the result.",
    "experiment": "Open the scenario, keep its network and stimulus fixed, and inspect the stated observation. Compare with the derived answer before changing one variable.",
    "explanation": "Forward current is +V/Z0; backward current is −V/Z0. Sum the waves at the same boundary. The launch divider matters: the incident wave is not generally the full source voltage.",
    "transferQuestion": "If the source resistance changes, does the load reflection coefficient change?",
    "answer": "No, ΓL depends on the line and load. Source resistance changes the launched amplitude and the later source reflection."
  },
  "limitations": [
    "Uniform lossless line; ideal source/load; no parasitic package or connector.",
    "The stated time is a settled first-arrival observation, not a finite-edge midpoint.",
    "No lossless-line result is a hardware compliance verdict."
  ],
  "scenario": "/topics/labs/travelling-waves.html#lab=labWaves;v=2.2;lw-z0=50;lw-rs=50;lw-rl=75;lw-open=0;lw-len=3;lw-tr=60;lw-xp=100;lw-t=1020",
  "timePs": 1020,
  "parameterUnits": {
    "Z0": "ohm",
    "Rs": "ohm",
    "RL": "ohm",
    "open": "boolean",
    "tr": "ps (full edge support)",
    "len": "in",
    "xp": "% of line"
  },
  "stimulus": "1 V source step; cubic smoothstep centred at zero; timePs specifies observation."
}