Ohm’s Law Visual Explorer — Code Walkthrough

HTML scaffolding

The root page is a single document that combines three major areas: the header/intro copy, the form-driven calculator, and the visual circuit explanation. Lines 15‑310 define that layout inside three <section> siblings plus the footer. The calculator section holds three numeric inputs, the clear button, and the area for results/explanation, while the new visual pulse section adds the animated circuit diagram and the slider that controls pulse speed.

<main>
  <section>heading + formula description</section>
  <section class="calculator">inputs + computed text</section>
  <section>scenario copy</section>
  <section>diagram + slider</section>
</main>

Visual styling and animation

Lines 8‑220 set the visual tone. CSS variables (--pulse-speed and --led-glow) allow the script to adjust animation timing and LED glow intensity. The .diagram — inside the new visual section — stacks wires and an LED circle with gradients and keyframe animations to hint at a real circuit. Range inputs inherit the body font, and the LED’s pseudo-element pulses with @keyframes glow so it looks alive when current increases.

:root { --pulse-speed: 1.2s; --led-glow: 0.5; }
.diagram { position: relative; ... }
.wire { animation: flow var(--pulse-speed) ... }
.led::after { animation: glow var(--pulse-speed) ... }

Calculator script logic

Lines 312‑396 load DOM references to the inputs, buttons, and new visual elements. The update() helper reads voltage/current/resistance, ensures exactly two values are filled, calculates the missing third by applying V = I × R, and updates the textual result with units. After every calculation it calls updateVisualizer() so the LED glow (via --led-glow) reflects the current magnitude.

If a user tries to fill all three values or fewer than two, friendly instructions appear instead. The reset button clears all inputs and resets the visualization.

Pulse control script

The slider in the visual section modifies --pulse-speed directly. updatePulseSpeed() (lines 388‑396) reads the slider, updates the CSS variable, and writes the current value back into the helper text. The slider’s input event keeps the animation fluid.

pulseSpeedInput.addEventListener("input", updatePulseSpeed);
updatePulseSpeed();

Resistance color code picker

A dropdown for each band (two significant digits, multiplier, tolerance) is populated with the standardized color-digit mapping using populateColorSelect(). When you click “Decode Colors,” the script multiplies the two-digit number by the selected multiplier, then shows the rounded result plus the tolerance text inside #colorValue. The event handler lives at lines 322‑347 in the main page.

decodeColorButton.addEventListener("click", decodeColors);
function decodeColors() {
  const digits = [band1Select.value, band2Select.value];
  const multiplier = parseFloat(multiplierSelect.value);
  ...
}

Visual feedback tying it together

updateVisualizer() clamps the effective LED glow between 0.5 and 2.3 by adjusting --led-glow. The script feeds it either the computed current or the manually entered current so the LED pulses brighter for larger current values.

function updateVisualizer(current) {
  const intensity = Math.min(1, Math.abs(current || 0) / 5);
  document.documentElement.style.setProperty("--led-glow", `${0.5 + intensity * 1.8}`);
}