// electricity · V = IR

Circuit Lab

Pick a component from the toolbar, then click the grid to place it

Select a component to adjust its value

Study the circuit diagram above, then calculate the answer below.

About Circuit Lab

  1. Placing components. Click a component button in the toolbar (Battery, Resistor, Bulb, LED, Motor, Switch), then click on the grid to place it. Press R to rotate before placing.
  2. Drawing wires. Select the Wire tool (or press W), click a component terminal (the dot at each end), then click another terminal to connect them with a wire.
  3. Adjusting values. In Select mode, click a component to select it. A slider appears below the canvas to change its resistance or voltage.
  4. Switches. Click any switch to toggle it on/off. An open switch breaks the circuit and stops current flow.
  5. LEDs & Motors. LEDs glow with their chosen color when current flows — select one and pick a color from the palette. Motors show a spinning indicator when powered. Both behave as resistive loads.
  6. Circuit analysis. When you build a complete circuit (battery + components + wires forming a closed loop), the side panel shows total resistance, current, power, and per-component readings.
  7. Practice mode. Switch to Practice to solve randomly generated series and parallel circuit problems. Calculate total resistance, current, or voltage drops.
Tip: Start simple — place a battery and a resistor, then wire their terminals in a loop. Add a bulb or LED to see it glow when current flows!