<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Stored Energy in a Capacitor</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: transparent;
      color: #0f172a;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 10px 12px;
      gap: 10px;
      width: 100%;
      max-width: 560px;
      margin: 0 auto;
      user-select: none;
    }

    /* Formula Toggle Bar */
    .formula-nav {
      display: flex;
      gap: 8px;
      width: 100%;
      justify-content: center;
    }

    .nav-btn {
      flex: 1;
      padding: 7px 6px;
      background: #ffffff;
      border: 1.5px solid #cbd5e1;
      border-radius: 8px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
      white-space: nowrap;
    }

    .nav-btn:hover {
      background: #f8fafc;
      border-color: #94a3b8;
    }

    .nav-btn.active {
      background: #eff6ff;
      border-color: #2563eb;
      color: #1d4ed8;
      font-weight: 700;
    }

    /* Graph Area */
    .graph-wrapper {
      width: 100%;
      position: relative;
    }

    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }

    .axis-line {
      stroke: #475569;
      stroke-width: 2;
      stroke-linecap: round;
    }

    .grid-line {
      stroke: #e2e8f0;
      stroke-width: 1;
      stroke-dasharray: 2, 2;
    }

    .slope-line {
      stroke: #2563eb;
      stroke-width: 3;
      stroke-linecap: round;
    }

    .dash-line {
      stroke: #64748b;
      stroke-width: 1.5;
      stroke-dasharray: 4, 4;
    }

    .area-fill {
      fill: #3b82f6;
      fill-opacity: 0.18;
      transition: d 0.05s linear;
    }

    .axis-title {
      font-size: 13px;
      font-weight: 700;
      fill: #1e293b;
    }

    .tick-label {
      font-size: 12px;
      fill: #475569;
      font-weight: 600;
    }

    /* Controls & Explanations */
    .controls-row {
      width: 100%;
      display: flex;
      align-items: center;
      gap: 12px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 12px;
    }

    .control-label {
      font-size: 13px;
      font-weight: 600;
      color: #334155;
      white-space: nowrap;
    }

    input[type="range"] {
      flex: 1;
      accent-color: #2563eb;
      cursor: pointer;
      height: 6px;
    }

    .slider-val {
      min-width: 48px;
      text-align: right;
      font-size: 13px;
      font-weight: 700;
      color: #2563eb;
      font-variant-numeric: tabular-nums;
    }

    /* Info Banner */
    .info-banner {
      width: 100%;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-left: 4px solid #2563eb;
      border-radius: 8px;
      padding: 8px 12px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      gap: 10px;
    }

    .formula-math {
      font-size: 15px;
      font-weight: 700;
      color: #1e293b;
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .frac {
      display: inline-flex;
      flex-direction: column;
      vertical-align: middle;
      text-align: center;
      font-size: 0.85em;
      line-height: 1.1;
      padding: 0 2px;
    }

    .frac-top {
      border-bottom: 1.5px solid currentColor;
      padding-bottom: 1px;
    }

    .frac-bottom {
      padding-top: 1px;
    }

    .formula-desc {
      font-size: 12px;
      font-weight: 600;
      color: #475569;
      background: #e2e8f0;
      padding: 3px 8px;
      border-radius: 4px;
      text-align: right;
    }

    @media (max-width: 440px) {
      .nav-btn {
        font-size: 11px;
        padding: 6px 4px;
      }
      .formula-math {
        font-size: 13px;
      }
      .formula-desc {
        font-size: 11px;
      }
    }
  </style>
</head>
<body>

  
  <div class="formula-nav">
    <button class="nav-btn active" id="btn-0" onclick="setFormula(0)">
      <i>E</i> = ½<i>QV</i>
    </button>
    <button class="nav-btn" id="btn-1" onclick="setFormula(1)">
      <i>E</i> = ½<i>CV</i>²
    </button>
    <button class="nav-btn" id="btn-2" onclick="setFormula(2)">
      <i>E</i> = <i>Q</i>² / (2<i>C</i>)
    </button>
  </div>

  
  <div class="graph-wrapper">
    <svg viewBox="-40 0 465 235" id="graph">
      
      <line x1="55" y1="40" x2="385" y2="40" class="grid-line" />
      <line x1="55" y1="85" x2="385" y2="85" class="grid-line" />
      <line x1="55" y1="130" x2="385" y2="130" class="grid-line" />
      <line x1="55" y1="175" x2="385" y2="175" class="grid-line" />
      
      <line x1="137.5" y1="205" x2="137.5" y2="30" class="grid-line" />
      <line x1="220" y1="205" x2="220" y2="30" class="grid-line" />
      <line x1="302.5" y1="205" x2="302.5" y2="30" class="grid-line" />
      <line x1="385" y1="205" x2="385" y2="30" class="grid-line" />

      
      <path id="energy-area" class="area-fill" />

      
      <line id="v-dash" class="dash-line" />
      <line id="q-dash" class="dash-line" />

      
      <line id="slope-line" class="slope-line" />

      
      <line x1="55" y1="205" x2="395" y2="205" class="axis-line" />
      <line x1="55" y1="205" x2="55" y2="18" class="axis-line" />

      
      <polygon points="398,205 390,201 390,209" fill="#475569" />
      <polygon points="55,14 51,22 59,22" fill="#475569" />

      
      <text x="395" y="222" class="axis-title" text-anchor="end">Voltage (V)</text>
      <text x="50" y="16" class="axis-title" text-anchor="end">Charge (Q)</text>
      <text x="47" y="218" class="tick-label" text-anchor="end">0</text>

      
      <circle id="point-marker" r="5" fill="#2563eb" stroke="#ffffff" stroke-width="2" />

      
      <text id="q-val-label" x="47" class="tick-label" text-anchor="end" fill="#2563eb" font-weight="700">Q</text>
      <text id="v-val-label" y="220" class="tick-label" text-anchor="middle" fill="#2563eb" font-weight="700">V</text>

      
      <text id="area-title" font-weight="700" fill="#1d4ed8" text-anchor="middle" font-size="12">Stored Energy (E)</text>
      <text id="area-sub" font-weight="600" fill="#2563eb" text-anchor="middle" font-size="11">Area = ½ · Q · V</text>

      
      <g id="slope-group">
        <text id="slope-tag" font-size="11" font-weight="700" fill="#2563eb" text-anchor="middle">Slope = C</text>
      </g>
    </svg>
  </div>

  
  <div class="controls-row">
    <span class="control-label">Voltage (<i>V</i>):</span>
    <input type="range" id="vSlider" min="2" max="10" step="0.2" value="8" oninput="updateGraph()">
    <span class="slider-val" id="vDisp">8.0 V</span>
  </div>

  
  <div class="info-banner">
    <div class="formula-math" id="formula-display">
      <i>E</i> = <span class="frac"><span class="frac-top">1</span><span class="frac-bottom">2</span></span><i>QV</i>
    </div>
    <div class="formula-desc" id="formula-desc">Base Area of Triangle</div>
  </div>

  <script>
    const formulas = [
      {
        html: "<i>E</i> = <span class=\"frac\"><span class=\"frac-top\">1</span><span class=\"frac-bottom\">2</span></span><i>QV</i>",
        desc: "Base Triangular Area",
        subText: "Area = ½ · Q · V"
      },
      {
        html: "<i>E</i> = <span class=\"frac\"><span class=\"frac-top\">1</span><span class=\"frac-bottom\">2</span></span><i>CV</i>²",
        desc: "Substitute Q = CV",
        subText: "Q = CV  ⇒  E = ½(CV)V"
      },
      {
        html: "<i>E</i> = <span class=\"frac\"><span class=\"frac-top\"><i>Q</i>²</span><span class=\"frac-bottom\">2<i>C</i></span></span>",
        desc: "Substitute V = Q / C",
        subText: "V = Q/C  ⇒  E = ½Q(Q/C)"
      }
    ];

    let currentForm = 0;
    const originX = 55;
    const originY = 205;
    const maxPlotX = 370;
    const maxPlotY = 35;

    function setFormula(index) {
      currentForm = index;
      for (let i = 0; i < 3; i++) {
        const btn = document.getElementById(`btn-${i}`);
        if (i === index) {
          btn.classList.add('active');
        } else {
          btn.classList.remove('active');
        }
      }

      const item = formulas[index];
      document.getElementById('formula-display').innerHTML = item.html;
      document.getElementById('formula-desc').textContent = item.desc;
      document.getElementById('area-sub').textContent = item.subText;
      updateGraph();
    }

    function updateGraph() {
      const vVal = parseFloat(document.getElementById('vSlider').value);
      document.getElementById('vDisp').textContent = vVal.toFixed(1) + " V";

      // Scale calculations: V from 0 to 10 mapped to X (55 to 370), Y (205 to 35)
      const pxPerV = (maxPlotX - originX) / 10;
      const pyPerQ = (originY - maxPlotY) / 10;

      const curX = originX + vVal * pxPerV;
      const curY = originY - vVal * pyPerQ;

      // Area under curve polygon
      const areaPath = `M ${originX} ${originY} L ${curX} ${originY} L ${curX} ${curY} Z`;
      document.getElementById('energy-area').setAttribute('d', areaPath);

      // Line representing Q = CV
      const maxExtX = Math.min(385, curX + 30);
      const maxExtY = originY - (maxExtX - originX) * ((originY - maxPlotY) / (maxPlotX - originX));
      
      const slopeLine = document.getElementById('slope-line');
      slopeLine.setAttribute('x1', originX);
      slopeLine.setAttribute('y1', originY);
      slopeLine.setAttribute('x2', maxExtX);
      slopeLine.setAttribute('y2', maxExtY);

      // Dashed projection lines
      const vDash = document.getElementById('v-dash');
      vDash.setAttribute('x1', curX);
      vDash.setAttribute('y1', originY);
      vDash.setAttribute('x2', curX);
      vDash.setAttribute('y2', curY);

      const qDash = document.getElementById('q-dash');
      qDash.setAttribute('x1', originX);
      qDash.setAttribute('y1', curY);
      qDash.setAttribute('x2', curX);
      qDash.setAttribute('y2', curY);

      // Point marker
      const marker = document.getElementById('point-marker');
      marker.setAttribute('cx', curX);
      marker.setAttribute('cy', curY);

      // Dynamic Tick Labels
      const qLabel = document.getElementById('q-val-label');
      qLabel.setAttribute('y', curY + 4);

      const vLabel = document.getElementById('v-val-label');
      vLabel.setAttribute('x', curX);

      // Triangle centroid for labels
      const centroidX = originX + (curX - originX) * 0.65;
      const centroidY = originY - (originY - curY) * 0.33;

      const title = document.getElementById('area-title');
      const sub = document.getElementById('area-sub');

      title.setAttribute('x', centroidX);
      title.setAttribute('y', centroidY - 4);
      sub.setAttribute('x', centroidX);
      sub.setAttribute('y', centroidY + 12);

      // Hide or adjust area text if triangle gets too small
      const showText = vVal >= 3.5;
      title.style.display = showText ? "block" : "none";
      sub.style.display = showText ? "block" : "none";

      // Slope annotation text positioned along the middle of the drawn line
      const midX = originX + (curX - originX) * 0.42;
      const midY = originY - (originY - curY) * 0.42;
      const slopeTag = document.getElementById('slope-tag');
      slopeTag.setAttribute('x', midX - 16);
      slopeTag.setAttribute('y', midY - 10);
    }

    // Initialize graph on load
    updateGraph();
  </script>
</body>
</html>

Capacitance and Charge Storage in Electronic Circuits

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Strobe Circuit Diagram</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8fafc;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 10px;
      min-height: 100vh;
      user-select: none;
      overflow-x: hidden;
    }

    .container {
      width: 100%;
      max-width: 620px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
    }

    /* Subsystem Flow Layout */
    .circuit-flow {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      gap: 6px;
    }

    .subsystem {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      background: #ffffff;
      border: 1px solid #cbd5e1;
      border-radius: 8px;
      padding: 8px 6px;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
      flex: 1;
      min-width: 0;
      min-height: 125px;
      text-align: center;
    }

    .sub-title {
      font-size: 11px;
      font-weight: 700;
      color: #475569;
      text-transform: uppercase;
      letter-spacing: 0.3px;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
      max-width: 100%;
    }

    .comp-stage {
      height: 56px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 2px 0;
    }

    /* Component: Battery */
    .batt-icon {
      width: 30px;
      height: 48px;
      border: 2px solid #334155;
      border-radius: 4px;
      position: relative;
      background: #f1f5f9;
      display: flex;
      align-items: flex-end;
      padding: 2px;
    }
    .batt-icon::before {
      content: '';
      position: absolute;
      top: -5px;
      left: 7px;
      width: 12px;
      height: 4px;
      background: #334155;
      border-radius: 2px 2px 0 0;
    }
    .batt-fill {
      width: 100%;
      height: 80%;
      background: #10b981;
      border-radius: 2px;
    }

    /* Component: Boost Converter */
    .boost-icon {
      width: 48px;
      height: 48px;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      background: #eff6ff;
      border: 1.5px dashed #3b82f6;
      border-radius: 6px;
      font-size: 10px;
      font-weight: 800;
      color: #1d4ed8;
      line-height: 1.25;
    }

    /* Component: Capacitor */
    .cap-cylinder {
      width: 38px;
      height: 52px;
      background: #1e293b;
      border-radius: 5px;
      position: relative;
      overflow: hidden;
      display: flex;
      flex-direction: column-reverse;
      padding: 2px;
      box-shadow: inset 0 0 4px rgba(0,0,0,0.5);
    }
    .cap-stripe {
      position: absolute;
      top: 0;
      right: 3px;
      width: 6px;
      height: 100%;
      background: rgba(255,255,255,0.22);
      display: flex;
      flex-direction: column;
      justify-content: space-around;
      align-items: center;
      font-size: 7px;
      color: #fff;
      font-weight: bold;
      z-index: 2;
    }
    .cap-fill {
      width: 100%;
      height: 100%;
      background: linear-gradient(180deg, #00f2fe 0%, #38bdf8 100%);
      border-radius: 2px;
      box-shadow: 0 0 8px #38bdf8;
      transition: height 0.04s ease-out;
    }

    /* Component: Flash Tube */
    .tube-housing {
      width: 42px;
      height: 52px;
      background: #f1f5f9;
      border: 1.5px solid #94a3b8;
      border-radius: 6px;
      position: relative;
      display: flex;
      justify-content: center;
      align-items: center;
      overflow: hidden;
    }
    .tube-glass {
      width: 14px;
      height: 42px;
      background: #e2e8f0;
      border-radius: 7px;
      position: relative;
      display: flex;
      justify-content: center;
      align-items: center;
      border: 1px solid #cbd5e1;
    }
    .tube-spark {
      position: absolute;
      inset: 0;
      background: #ffffff;
      opacity: 0;
      filter: blur(1.5px);
      box-shadow: 0 0 20px 8px #ffffff, 0 0 35px 15px #38bdf8;
      border-radius: 50%;
      pointer-events: none;
      transition: opacity 0.04s ease-out;
    }

    .sub-value {
      font-size: 11px;
      font-weight: 700;
      color: #0f172a;
      white-space: nowrap;
    }
    .sub-desc {
      font-size: 9.5px;
      color: #64748b;
      white-space: nowrap;
    }

    /* Flow Arrows */
    .flow-arrow {
      font-size: 16px;
      color: #94a3b8;
      font-weight: 800;
      flex-shrink: 0;
    }

    /* Controls & Trigger */
    .control-section {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
    }

    .fire-btn {
      background: #ef4444;
      color: #ffffff;
      border: none;
      border-radius: 20px;
      padding: 8px 22px;
      font-size: 13px;
      font-weight: 700;
      cursor: pointer;
      box-shadow: 0 2px 6px rgba(239, 68, 68, 0.35);
      display: flex;
      align-items: center;
      gap: 6px;
      outline: none;
      transition: opacity 0.15s, background-color 0.15s;
    }
    .fire-btn:hover:not(:disabled) {
      background: #dc2626;
    }
    .fire-btn:disabled {
      background: #94a3b8;
      box-shadow: none;
      cursor: not-allowed;
    }

    .status-text {
      font-size: 10px;
      font-weight: 700;
      color: #059669;
      letter-spacing: 0.4px;
      text-transform: uppercase;
    }

    /* Metrics Grid */
    .metrics-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      width: 100%;
    }

    .metric-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 4px;
      text-align: center;
      box-shadow: 0 1px 2px rgba(0,0,0,0.03);
      min-width: 0;
    }
    .metric-label {
      font-size: 10.5px;
      font-weight: 600;
      color: #64748b;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
    }
    .metric-formula {
      font-size: 12.5px;
      font-weight: 800;
      color: #0284c7;
      margin: 2px 0 1px;
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
    }
    .metric-sub {
      font-size: 9.5px;
      color: #94a3b8;
      white-space: nowrap;
    }

    /* Flash Screen Pulse Overlay */
    .flash-overlay {
      position: fixed;
      inset: 0;
      background: rgba(255,255,255,0.75);
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.04s ease-out;
      z-index: 100;
    }

    /* Responsive Adaptation for Mobile Screens <= 500px */
    @media (max-width: 500px) {
      body {
        padding: 8px 6px;
      }
      .container {
        gap: 8px;
      }
      .circuit-flow {
        display: grid;
        grid-template-columns: 1fr 20px 1fr;
        grid-template-areas:
          "batt  arr1 boost"
          "cap   arr3 flash";
        gap: 6px 4px;
        align-items: center;
      }
      .sys-batt  { grid-area: batt; }
      .arr-1     { grid-area: arr1; justify-self: center; }
      .sys-boost { grid-area: boost; }
      .arr-2     { display: none; }
      .sys-cap   { grid-area: cap; }
      .arr-3     { grid-area: arr3; justify-self: center; }
      .sys-flash { grid-area: flash; }

      .subsystem {
        min-height: 112px;
        padding: 6px 4px;
      }
      .comp-stage {
        height: 48px;
      }
      .batt-icon { height: 42px; width: 28px; }
      .boost-icon { height: 42px; width: 44px; font-size: 9.5px; }
      .cap-cylinder { height: 44px; width: 34px; }
      .tube-housing { height: 44px; width: 38px; }
      .tube-glass { height: 36px; width: 12px; }

      .metrics-grid {
        gap: 4px;
      }
      .metric-card {
        padding: 6px 2px;
      }
      .metric-label {
        font-size: 9.5px;
      }
      .metric-formula {
        font-size: 11px;
      }
      .metric-sub {
        font-size: 8.5px;
      }
    }
  </style>
</head>
<body>

  <div id="flashOverlay" class="flash-overlay"></div>

  <div class="container">
    
    <div class="circuit-flow">
      
      <div class="subsystem sys-batt">
        <div class="sub-title">1. Li-ion</div>
        <div class="comp-stage">
          <div class="batt-icon">
            <div class="batt-fill"></div>
          </div>
        </div>
        <div class="sub-value">3.7 V</div>
        <div class="sub-desc">DC Supply</div>
      </div>

      <div class="flow-arrow arr-1">→</div>

      
      <div class="subsystem sys-boost">
        <div class="sub-title">2. Boost</div>
        <div class="comp-stage">
          <div class="boost-icon">
            <span>3.7V</span>
            <span>↓</span>
            <span>330V</span>
          </div>
        </div>
        <div class="sub-value">Step-Up</div>
        <div class="sub-desc">DC-DC</div>
      </div>

      <div class="flow-arrow arr-2">→</div>

      
      <div class="subsystem sys-cap">
        <div class="sub-title">3. Capacitor</div>
        <div class="comp-stage">
          <div class="cap-cylinder">
            <div class="cap-stripe">
              <span>-</span><span>-</span><span>-</span>
            </div>
            <div id="capFill" class="cap-fill"></div>
          </div>
        </div>
        <div id="capVoltage" class="sub-value">330 V</div>
        <div class="sub-desc">220 µF Storage</div>
      </div>

      <div class="flow-arrow arr-3">→</div>

      
      <div class="subsystem sys-flash">
        <div class="sub-title">4. Xenon</div>
        <div class="comp-stage">
          <div class="tube-housing">
            <div class="tube-glass">
              <div id="tubeSpark" class="tube-spark"></div>
            </div>
          </div>
        </div>
        <div class="sub-value">Flash Tube</div>
        <div class="sub-desc">Trigger Switch</div>
      </div>
    </div>

    
    <div class="control-section">
      <button id="fireBtn" class="fire-btn">⚡ Fire Flash</button>
      <div id="statusLabel" class="status-text">Ready to Fire</div>
    </div>

    
    <div class="metrics-grid">
      <div class="metric-card">
        <div class="metric-label">Charge Stored</div>
        <div class="metric-formula">Q = 72.6 mC</div>
        <div class="metric-sub">Q = C · V</div>
      </div>
      <div class="metric-card">
        <div class="metric-label">Stored Energy</div>
        <div class="metric-formula">E = 11.98 J</div>
        <div class="metric-sub">½ C · V²</div>
      </div>
      <div class="metric-card">
        <div class="metric-label">Peak Discharge</div>
        <div class="metric-formula">P = 11.98 kW</div>
        <div class="metric-sub">Δt = 1 ms</div>
      </div>
    </div>
  </div>

  <script>
    const fireBtn = document.getElementById('fireBtn');
    const capFill = document.getElementById('capFill');
    const capVoltage = document.getElementById('capVoltage');
    const tubeSpark = document.getElementById('tubeSpark');
    const flashOverlay = document.getElementById('flashOverlay');
    const statusLabel = document.getElementById('statusLabel');

    let audioCtx = null;
    function playPop() {
      try {
        if (!audioCtx) audioCtx = new (window.AudioContext || window.webkitAudioContext)();
        const buf = audioCtx.createBuffer(1, audioCtx.sampleRate * 0.05, audioCtx.sampleRate);
        const data = buf.getChannelData(0);
        for (let i = 0; i < data.length; i++) {
          data[i] = (Math.random() * 2 - 1) * Math.exp(-i / (audioCtx.sampleRate * 0.008));
        }
        const src = audioCtx.createBufferSource();
        src.buffer = buf;
        src.connect(audioCtx.destination);
        src.start();
      } catch (e) {}
    }

    function fireFlash() {
      fireBtn.disabled = true;
      playPop();

      // Instant discharge
      capFill.style.transition = 'height 0.03s ease-out';
      capFill.style.height = '0%';
      capVoltage.textContent = '0 V';
      statusLabel.textContent = 'Discharging...';
      statusLabel.style.color = '#ef4444';

      // Tube spark & flash overlay
      tubeSpark.style.opacity = '1';
      flashOverlay.style.opacity = '1';

      setTimeout(() => {
        tubeSpark.style.opacity = '0';
        flashOverlay.style.opacity = '0';
      }, 90);

      // Recharging cycle
      setTimeout(() => {
        statusLabel.textContent = 'Recharging...';
        statusLabel.style.color = '#3b82f6';
        capFill.style.transition = 'height 2.2s ease-in-out';
        capFill.style.height = '100%';

        let start = Date.now();
        let rechargeInterval = setInterval(() => {
          let progress = Math.min(1, (Date.now() - start) / 2200);
          capVoltage.textContent = Math.round(progress * 330) + ' V';
          if (progress >= 1) {
            clearInterval(rechargeInterval);
            fireBtn.disabled = false;
            statusLabel.textContent = 'Ready to Fire';
            statusLabel.style.color = '#059669';
          }
        }, 60);
      }, 350);
    }

    fireBtn.addEventListener('click', fireFlash);
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8f9fa;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px;
      user-select: none;
    }

    /* Equation Display Card */
    .formula-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 8px 16px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 16px;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
      width: 100%;
      max-width: 480px;
    }
    .eq-main {
      font-size: 16px;
      font-weight: 700;
      color: #1e2945;
      letter-spacing: 0.5px;
    }
    .eq-calc {
      font-size: 15px;
      font-weight: 600;
      color: #22b7ff;
      background: #f0f9ff;
      padding: 4px 10px;
      border-radius: 6px;
      border: 1px solid #bae6fd;
    }

    /* Diagram Container */
    .svg-container {
      width: 100%;
      max-width: 480px;
      height: 240px;
      position: relative;
    }
    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Controls */
    .control-panel {
      width: 100%;
      max-width: 480px;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 16px;
      display: flex;
      flex-direction: column;
      gap: 6px;
    }
    .control-header {
      display: flex;
      justify-content: space-between;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
    }
    .control-val {
      color: #1e2945;
      font-weight: 700;
    }
    input[type="range"] {
      -webkit-appearance: none;
      appearance: none;
      width: 100%;
      height: 6px;
      background: #e2e8f0;
      border-radius: 3px;
      outline: none;
      cursor: pointer;
    }
    input[type="range"]::-webkit-slider-thumb {
      -webkit-appearance: none;
      appearance: none;
      width: 18px;
      height: 18px;
      border-radius: 50%;
      background: #22b7ff;
      border: 2px solid #ffffff;
      box-shadow: 0 1px 4px rgba(0,0,0,0.25);
      cursor: pointer;
    }
    input[type="range"]::-moz-range-thumb {
      width: 18px;
      height: 18px;
      border-radius: 50%;
      background: #22b7ff;
      border: 2px solid #ffffff;
      box-shadow: 0 1px 4px rgba(0,0,0,0.25);
      cursor: pointer;
    }
  </style>
</head>
<body>

  
  <div class="formula-card">
    <div class="eq-main">Q = C · V</div>
    <div class="eq-calc" id="calcDisplay">Q = 60 µC</div>
  </div>

  
  <div class="svg-container">
    <svg viewBox="0 0 460 230">
      <defs>
        <marker id="arrow" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 0 1.5 L 8 5 L 0 8.5 z" fill="#22b7ff" />
        </marker>
        <linearGradient id="dielectricGrad" x1="0%" y1="0%" x2="0%" y2="100%">
          <stop offset="0%" stop-color="#f8fafc" />
          <stop offset="100%" stop-color="#f1f5f9" />
        </linearGradient>
      </defs>

      
      <rect x="110" y="25" width="240" height="170" fill="url(#dielectricGrad)" stroke="#e2e8f0" stroke-width="1.5" rx="4" />
      <text x="230" y="210" text-anchor="middle" font-size="12" font-weight="600" fill="#94a3b8" letter-spacing="1">DIELECTRIC LAYER</text>

      
      <g id="fieldLines"></g>

      
      <rect x="75" y="20" width="35" height="180" rx="4" fill="#fee2e2" stroke="#ef4444" stroke-width="2" />
      
      <rect x="350" y="20" width="35" height="180" rx="4" fill="#e0f2fe" stroke="#0284c7" stroke-width="2" />

      
      <text x="92.5" y="14" text-anchor="middle" font-size="13" font-weight="700" fill="#dc2626">+Q</text>
      <text x="367.5" y="14" text-anchor="middle" font-size="13" font-weight="700" fill="#0284c7">-Q</text>

      
      <g id="posCharges"></g>
      <g id="negCharges"></g>

      
      <path d="M 75 110 L 35 110" stroke="#94a3b8" stroke-width="2" stroke-dasharray="3,3" />
      <path d="M 385 110 L 425 110" stroke="#94a3b8" stroke-width="2" stroke-dasharray="3,3" />
      <circle cx="35" cy="110" r="3" fill="#ef4444" />
      <circle cx="425" cy="110" r="3" fill="#0284c7" />
      <text x="25" y="114" text-anchor="middle" font-size="12" font-weight="700" fill="#ef4444">+</text>
      <text x="435" y="114" text-anchor="middle" font-size="12" font-weight="700" fill="#0284c7">−</text>
    </svg>
  </div>

  
  <div class="control-panel">
    <div class="control-header">
      <span>Applied Voltage (V)</span>
      <span class="control-val" id="voltageVal">6.0 V</span>
    </div>
    <input type="range" id="vSlider" min="0" max="12" step="1" value="6">
  </div>

  <script>
    const C = 10; // fixed capacitance: 10 µF
    const vSlider = document.getElementById('vSlider');
    const voltageVal = document.getElementById('voltageVal');
    const calcDisplay = document.getElementById('calcDisplay');
    const posCharges = document.getElementById('posCharges');
    const negCharges = document.getElementById('negCharges');
    const fieldLines = document.getElementById('fieldLines');

    const totalSlots = 8;
    const yStart = 38;
    const ySpacing = 20.5;

    function render(V) {
      const Q = C * V;
      voltageVal.textContent = V.toFixed(1) + ' V';
      calcDisplay.textContent = `Q = ${Q} µC`;

      // Density of charges mapped proportionally to voltage
      const count = Math.round((V / 12) * totalSlots);

      // Render Positive & Negative Charges
      let posHTML = '';
      let negHTML = '';
      let fieldHTML = '';

      if (count > 0) {
        const step = (160) / (count + 1);
        for (let i = 1; i <= count; i++) {
          const y = 20 + i * step;

          // + on left plate
          posHTML += `
            <circle cx="92.5" cy="${y}" r="6.5" fill="#ef4444" />
            <text x="92.5" y="${y + 3.5}" text-anchor="middle" font-size="10" font-weight="bold" fill="#ffffff">+</text>
          `;

          // - on right plate
          negHTML += `
            <circle cx="367.5" cy="${y}" r="6.5" fill="#0284c7" />
            <text x="367.5" y="${y + 3.5}" text-anchor="middle" font-size="10" font-weight="bold" fill="#ffffff">−</text>
          `;

          // Electric field lines pointing Left -> Right
          fieldHTML += `
            <line x1="115" y1="${y}" x2="343" y2="${y}" stroke="#22b7ff" stroke-width="1.8" marker-end="url(#arrow)" stroke-dasharray="${V === 0 ? '4,4' : 'none'}" opacity="0.9" />
          `;
        }
      }

      posCharges.innerHTML = posHTML;
      negCharges.innerHTML = negHTML;
      fieldLines.innerHTML = fieldHTML;
    }

    vSlider.addEventListener('input', (e) => {
      render(parseFloat(e.target.value));
    });

    // Initial draw
    render(6);
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      width: 100%;
      min-height: 100%;
      background: #ffffff;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      justify-content: center;
      padding: 12px;
    }
    .grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      width: 100%;
      max-width: 680px;
      margin: 0 auto;
    }
    @media (max-width: 480px) {
      .grid {
        grid-template-columns: 1fr;
        gap: 10px;
      }
      .cap-card {
        display: grid;
        grid-template-columns: 80px 1fr;
        grid-template-rows: auto auto auto;
        gap: 4px 12px;
        align-items: center;
        text-align: left !important;
        padding: 10px 14px !important;
      }
      .cap-card .preview-box {
        grid-row: 1 / 4;
        margin-bottom: 0 !important;
      }
    }
    .cap-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 12px 8px;
      text-align: center;
      display: flex;
      flex-direction: column;
      align-items: center;
    }
    .title {
      font-size: 15px;
      font-weight: 700;
      margin-bottom: 8px;
      color: #0f172a;
    }
    .preview-box {
      width: 100%;
      height: 90px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 8px;
    }
    .schematic-box {
      width: 100%;
      height: 38px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 8px;
      background: #ffffff;
      border: 1px dashed #cbd5e1;
      border-radius: 6px;
    }
    .badge-group {
      display: flex;
      flex-direction: column;
      gap: 4px;
      width: 100%;
    }
    .badge {
      font-size: 12px;
      font-weight: 600;
      padding: 4px 6px;
      border-radius: 6px;
      line-height: 1.2;
    }
    .badge-range {
      background: #e0f2fe;
      color: #0369a1;
    }
    .badge-nonpol {
      background: #f1f5f9;
      color: #475569;
    }
    .badge-pol {
      background: #fef2f2;
      color: #b91c1c;
    }
    svg {
      display: block;
      overflow: visible;
    }
  </style>
</head>
<body>

<div class="grid">
  
  <div class="cap-card">
    <div class="title">Ceramic</div>
    <div class="preview-box">
      <svg width="70" height="85" viewBox="0 0 70 85">
        
        <line x1="28" y1="42" x2="28" y2="82" stroke="#94a3b8" stroke-width="2.5" stroke-linecap="round"/>
        <line x1="42" y1="42" x2="42" y2="82" stroke="#94a3b8" stroke-width="2.5" stroke-linecap="round"/>
        
        <circle cx="35" cy="32" r="24" fill="#f59e0b"/>
        <circle cx="35" cy="32" r="24" fill="url(#ceramicGrad)"/>
        
        <text x="35" y="36" font-size="11" font-weight="700" fill="#78350f" text-anchor="middle" font-family="monospace">104</text>
        <defs>
          <radialGradient id="ceramicGrad" cx="30%" cy="30%" r="70%">
            <stop offset="0%" stop-color="#fbbf24" stop-opacity="0.8"/>
            <stop offset="100%" stop-color="#d97706" stop-opacity="0.9"/>
          </radialGradient>
        </defs>
      </svg>
    </div>
    <div class="schematic-box">
      <svg width="60" height="30" viewBox="0 0 60 30">
        <line x1="5" y1="15" x2="26" y2="15" stroke="#334155" stroke-width="2"/>
        <line x1="26" y1="5" x2="26" y2="25" stroke="#334155" stroke-width="2.5" stroke-linecap="round"/>
        <line x1="34" y1="5" x2="34" y2="25" stroke="#334155" stroke-width="2.5" stroke-linecap="round"/>
        <line x1="34" y1="15" x2="55" y2="15" stroke="#334155" stroke-width="2"/>
      </svg>
    </div>
    <div class="badge-group">
      <span class="badge badge-nonpol">Non-polarized</span>
      <span class="badge badge-range">1 pF – 100 nF</span>
    </div>
  </div>

  
  <div class="cap-card">
    <div class="title">Electrolytic</div>
    <div class="preview-box">
      <svg width="70" height="85" viewBox="0 0 70 85">
        
        <line x1="26" y1="50" x2="26" y2="84" stroke="#94a3b8" stroke-width="2.5" stroke-linecap="round"/>
        <line x1="44" y1="50" x2="44" y2="74" stroke="#94a3b8" stroke-width="2.5" stroke-linecap="round"/>
        
        <text x="26" y="80" font-size="9" font-weight="700" fill="#0284c7" text-anchor="middle" dx="-8">+</text>
        <text x="44" y="72" font-size="11" font-weight="700" fill="#64748b" text-anchor="middle" dx="8">−</text>
        
        <rect x="18" y="10" width="34" height="42" rx="4" fill="#0284c7"/>
        
        <rect x="20" y="8" width="30" height="3" rx="1.5" fill="#cbd5e1"/>
        
        <path d="M 41 10 h 11 v 42 h -11 z" fill="#e2e8f0"/>
        <text x="46.5" y="24" font-size="10" font-weight="900" fill="#0f172a" text-anchor="middle">−</text>
        <text x="46.5" y="38" font-size="10" font-weight="900" fill="#0f172a" text-anchor="middle">−</text>
      </svg>
    </div>
    <div class="schematic-box">
      <svg width="60" height="30" viewBox="0 0 60 30">
        
        <text x="14" y="10" font-size="10" font-weight="700" fill="#b91c1c" text-anchor="middle">+</text>
        <line x1="5" y1="15" x2="25" y2="15" stroke="#334155" stroke-width="2"/>
        <line x1="25" y1="5" x2="25" y2="25" stroke="#334155" stroke-width="2.5" stroke-linecap="round"/>
        
        <path d="M 35 5 Q 31 15 35 25" fill="none" stroke="#334155" stroke-width="2.5" stroke-linecap="round"/>
        <line x1="33" y1="15" x2="55" y2="15" stroke="#334155" stroke-width="2"/>
      </svg>
    </div>
    <div class="badge-group">
      <span class="badge badge-pol">Polarized (+ / −)</span>
      <span class="badge badge-range">1 µF – 47 mF</span>
    </div>
  </div>

  
  <div class="cap-card">
    <div class="title">Film</div>
    <div class="preview-box">
      <svg width="70" height="85" viewBox="0 0 70 85">
        
        <line x1="22" y1="46" x2="22" y2="82" stroke="#94a3b8" stroke-width="2.5" stroke-linecap="round"/>
        <line x1="48" y1="46" x2="48" y2="82" stroke="#94a3b8" stroke-width="2.5" stroke-linecap="round"/>
        
        <rect x="12" y="18" width="46" height="32" rx="3" fill="#e11d48"/>
        
        <path d="M 12 21 L 18 15 L 58 15 L 58 40 L 58 42 L 58 21 Z" fill="#be123c" opacity="0.3"/>
        <text x="35" y="37" font-size="10" font-weight="700" fill="#ffffff" text-anchor="middle" font-family="monospace">0.1µF</text>
      </svg>
    </div>
    <div class="schematic-box">
      <svg width="60" height="30" viewBox="0 0 60 30">
        <line x1="5" y1="15" x2="26" y2="15" stroke="#334155" stroke-width="2"/>
        <line x1="26" y1="5" x2="26" y2="25" stroke="#334155" stroke-width="2.5" stroke-linecap="round"/>
        <line x1="34" y1="5" x2="34" y2="25" stroke="#334155" stroke-width="2.5" stroke-linecap="round"/>
        <line x1="34" y1="15" x2="55" y2="15" stroke="#334155" stroke-width="2"/>
      </svg>
    </div>
    <div class="badge-group">
      <span class="badge badge-nonpol">Non-polarized</span>
      <span class="badge badge-range">1 nF – 10 µF</span>
    </div>
  </div>
</div>

</body>
</html>

ELEC-9.1

Aligned learning resources

Related diagrams