feat(components): Regulated Power Supply with per-instance current limit

Adds a new picker entry 'Regulated Power Supply' under the analog
category. Conceptually fills the gap between wokwi-battery (fixed
DC) and wokwi-signal-generator (waveform focus): user chooses
voltage + mode (dc / ac) + currentLimit, no need to think about
battery chemistry or signal amplitudes.

Properties:
  mode:         'dc' | 'ac'   (default 'dc')
  voltage:      V             (default 5)
  frequency:    Hz            (default 50, only for AC)
  currentLimit: A             (default 1)

Design notes:
  - No new Web Component. The tagName piggy-backs on
    wokwi-signal-generator so the canvas renders the familiar
    bench-instrument chrome — saves shipping a second 100+ LOC
    Web Component for an identical 2-pin shape.
  - SPICE: ideal V-source + ESR sized so a near-short reads
    I ≈ 1.5·limit. ngspice has no native foldback so the limit
    is a circuitVerifier rule, not a hard SPICE constraint.
  - circuitVerifier: extends sourceComponents regex to include
    power-supply AND honors the per-instance currentLimit
    property as the threshold. Real bench supplies behave this
    way — a 100mA-limited supply trips at 100mA, a 5A supply
    tolerates 5A before flagging. The error code is
    'source-overload' (not 'short-circuit') so the modal copy
    matches what the user just configured.

The board GND / VCC pins of Arduino / ESP32 / etc. already act
as voltage sources via BOARD_PIN_GROUPS canonicalisation (the
NetlistBuilder maps wires to the right rail). So the user's
companion request — 'board pins should already work' — is the
existing behaviour; this commit only adds the standalone bench
supply for boardless circuits or for testing with a different
voltage.

frontend/public/components-metadata.json

@@ -517,6 +517,66 @@
       "category": "analog",
       "description": "Single-channel optocoupler. CTR 80–600% (typ. 100%). Higher drive than 4N25, commonly used for MCU-to-mains isolation."
     },
+    {
+      "thumbnail": "<svg width=\"64\" height=\"64\" xmlns=\"http://www.w3.org/2000/svg\">\n      <rect width=\"64\" height=\"64\" fill=\"#1a2332\" rx=\"4\"/>\n      <rect x=\"10\" y=\"14\" width=\"44\" height=\"30\" fill=\"#2a3548\" rx=\"3\" stroke=\"#4a5878\"/>\n      <text x=\"32\" y=\"30\" text-anchor=\"middle\" font-size=\"9\" font-family=\"monospace\" fill=\"#4ade80\" font-weight=\"bold\">5.00V</text>\n      <text x=\"32\" y=\"40\" text-anchor=\"middle\" font-size=\"7\" font-family=\"monospace\" fill=\"#fbbf24\">1.00A</text>\n      <circle cx=\"18\" cy=\"52\" r=\"3\" fill=\"#dc2626\"/>\n      <circle cx=\"46\" cy=\"52\" r=\"3\" fill=\"#0f172a\" stroke=\"#64748b\"/>\n      <text x=\"32\" y=\"60\" text-anchor=\"middle\" font-size=\"6\" fill=\"#9d9d9d\">PSU</text>\n    </svg>",
+      "tags": [
+        "power-supply",
+        "regulated",
+        "source",
+        "psu",
+        "bench",
+        "lab",
+        "dc",
+        "ac",
+        "analog"
+      ],
+      "properties": [
+        {
+          "name": "mode",
+          "type": "string",
+          "defaultValue": "dc",
+          "control": "select",
+          "options": [
+            "dc",
+            "ac"
+          ],
+          "description": "DC for fixed rails, AC for sine waveform output"
+        },
+        {
+          "name": "voltage",
+          "type": "number",
+          "defaultValue": 5,
+          "control": "text",
+          "description": "Output voltage in V (DC mode) or peak amplitude (AC mode)"
+        },
+        {
+          "name": "frequency",
+          "type": "number",
+          "defaultValue": 50,
+          "control": "text",
+          "description": "Frequency in Hz (AC mode only)"
+        },
+        {
+          "name": "currentLimit",
+          "type": "number",
+          "defaultValue": 1,
+          "control": "text",
+          "description": "Maximum sourced current in A. The verifier warns when exceeded."
+        }
+      ],
+      "defaultValues": {
+        "mode": "dc",
+        "voltage": 5,
+        "frequency": 50,
+        "currentLimit": 1
+      },
+      "pinCount": 2,
+      "id": "power-supply",
+      "tagName": "wokwi-signal-generator",
+      "name": "Regulated Power Supply",
+      "category": "analog",
+      "description": "Bench DC/AC power supply with optional current limit. DC mode for fixed rails; AC mode for sine. Verifier enforces the current limit per instance."
+    },
     {
       "thumbnail": "<svg width=\"64\" height=\"64\" xmlns=\"http://www.w3.org/2000/svg\">\n      <rect width=\"64\" height=\"64\" fill=\"#e0e0e0\" rx=\"4\"/>\n      <text x=\"50%\" y=\"50%\" text-anchor=\"middle\" dy=\".3em\" font-size=\"10\" fill=\"#666\">\n        SIGNAL-GENERATOR\n      </text>\n    </svg>",
       "tags": [

frontend/src/simulation/spice/componentToSpice.ts

@@ -548,6 +548,41 @@ const MAPPERS: Record<string, Mapper> = {
     };
   },
 
+  // ── Regulated power supply (DC / AC, current-limit aware) ───────────────
+  // Properties:
+  //   mode:         'dc' | 'ac'   (default 'dc')
+  //   voltage:      V             (default 5)
+  //   frequency:    Hz            (default 50, only used in AC mode)
+  //   currentLimit: A             (default 1; enforced by circuitVerifier,
+  //                                NOT SPICE — ngspice has no native
+  //                                foldback limiter)
+  // The visual element reuses wokwi-signal-generator (no new Web Component
+  // needed). ESR is derived from the currentLimit so a near-short reads
+  // as I ≈ 1.5·limit, which the verifier then flags as source-overload.
+  'power-supply': (comp, netLookup) => {
+    const pos = netLookup('+') ?? netLookup('SIG') ?? netLookup('VCC');
+    const neg = netLookup('−') ?? netLookup('-') ?? netLookup('GND');
+    if (!pos || !neg) return null;
+    const mode = String(comp.properties.mode ?? 'dc').toLowerCase();
+    const voltage = Number(comp.properties.voltage ?? 5);
+    const currentLimit = Math.max(0.01, Number(comp.properties.currentLimit ?? 1));
+    const esr = Math.max(0.01, voltage / (currentLimit * 1.5));
+    let source: string;
+    if (mode === 'ac') {
+      const freq = Number(comp.properties.frequency ?? 50);
+      source = `SIN(0 ${voltage} ${freq})`;
+    } else {
+      source = `DC ${voltage}`;
+    }
+    return {
+      cards: [
+        `V_${comp.id} ${pos} ${comp.id}_int ${source}`,
+        `R_${comp.id}_esr ${comp.id}_int ${neg} ${esr}`,
+      ],
+      modelsUsed: new Set(),
+    };
+  },
+
   // ── Signal generator (AC / pulse / DC) ───────────────────────────────────
   // Properties:
   //   waveform: 'sine' | 'square' | 'dc'   (default 'sine')

frontend/src/simulation/verify/circuitVerifier.ts

@@ -128,22 +128,36 @@ export async function verifyCircuit(
   const branchCurrents = solve.branchCurrents;
 
   // ── Rule 1: short circuit / power source overload ──────────────────────
-  // Every voltage source (battery / signal-generator) emits a branch current
+  // Every voltage source (battery / signal-generator / power-supply) emits
-  // `i(v_<id>)`. SPICE convention: V-source's current is measured + → −
+  // a branch current `i(v_<id>)`. SPICE convention: V-source's current is
-  // INTERNALLY, so external current draw is the absolute value.
+  // measured + → − INTERNALLY, so external current draw is the absolute
+  // value.
+  //
+  // power-supply components carry a per-instance `currentLimit` property
+  // that overrides the global short-circuit threshold — that matches what
+  // a real bench supply does: a 100mA-limited supply trips at 100mA, a
+  // 5A-limited supply tolerates up to 5A before flagging fault.
   const sourceComponents = input.components.filter((c) =>
-    /^(battery|signal-generator)/.test(c.metadataId),
+    /^(battery|signal-generator|power-supply)/.test(c.metadataId),
   );
   for (const src of sourceComponents) {
     const i = Math.abs(branchCurrents[`v_${src.id}`] ?? 0);
-    if (i >= config.shortCircuitAmps) {
+    const perInstanceLimit =
+      src.metadataId === 'power-supply'
+        ? Number(src.properties?.currentLimit ?? config.shortCircuitAmps)
+        : config.shortCircuitAmps;
+    const threshold = Number.isFinite(perInstanceLimit) && perInstanceLimit > 0
+      ? perInstanceLimit
+      : config.shortCircuitAmps;
+    if (i >= threshold) {
+      const isPsu = src.metadataId === 'power-supply';
       errors.push({
         severity: 'error',
-        code: 'short-circuit',
+        code: isPsu ? 'source-overload' : 'short-circuit',
         componentId: src.id,
-        message: `Possible short circuit — ${src.metadataId} ${src.id} is delivering ${formatAmps(
+        message: isPsu
-          i,
+          ? `Power supply ${src.id} is being asked for ${formatAmps(i)} — past its ${formatAmps(threshold)} current limit. A real bench supply would foldback or cut out. Raise the currentLimit or add more series resistance to the load.`
-        )} (threshold ${formatAmps(config.shortCircuitAmps)}). Check for 5 V tied directly to GND.`,
+          : `Possible short circuit — ${src.metadataId} ${src.id} is delivering ${formatAmps(i)} (threshold ${formatAmps(threshold)}). Check for power tied directly to GND.`,
         metric: i,
       });
     }

scripts/component-overrides.json

@@ -1044,6 +1044,65 @@
         "analog"
       ]
     },
+    {
+      "id": "power-supply",
+      "tagName": "wokwi-signal-generator",
+      "name": "Regulated Power Supply",
+      "category": "analog",
+      "description": "Bench DC/AC power supply with optional current limit. DC mode for fixed rails (5V, 12V, etc.); AC mode for sine sources. Visually shares the signal-generator chassis so no new Web Component is needed. The current limit is enforced by the circuit verifier — if any load pulls more than the configured amperage, Run is blocked with a 'source-overload' warning, mimicking a real bench supply's foldback behavior.",
+      "properties": [
+        {
+          "name": "mode",
+          "type": "string",
+          "defaultValue": "dc",
+          "control": "select",
+          "options": [
+            "dc",
+            "ac"
+          ],
+          "description": "DC for fixed rails, AC for sine waveform output"
+        },
+        {
+          "name": "voltage",
+          "type": "number",
+          "defaultValue": 5,
+          "control": "text",
+          "description": "Output voltage in V (DC mode) or peak amplitude (AC mode)"
+        },
+        {
+          "name": "frequency",
+          "type": "number",
+          "defaultValue": 50,
+          "control": "text",
+          "description": "Frequency in Hz (AC mode only)"
+        },
+        {
+          "name": "currentLimit",
+          "type": "number",
+          "defaultValue": 1,
+          "control": "text",
+          "description": "Maximum sourced current in A. The verifier warns when exceeded."
+        }
+      ],
+      "defaultValues": {
+        "mode": "dc",
+        "voltage": 5,
+        "frequency": 50,
+        "currentLimit": 1
+      },
+      "pinCount": 2,
+      "tags": [
+        "power-supply",
+        "regulated",
+        "source",
+        "psu",
+        "bench",
+        "lab",
+        "dc",
+        "ac",
+        "analog"
+      ]
+    },
     {
       "id": "signal-generator",
       "tagName": "wokwi-signal-generator",