Christmas Lights: Series vs Parallel Circuits (2D Schematic)

This is a real schematic circuit diagram of a Christmas light string — a battery symbol, wires, and bulb symbols drawn as resistors, not a flattened view of a physical string. Toggle between a single series loop and a two-rail parallel ladder, tune the bulb count, source voltage and bulb resistance, and click any bulb symbol to burn it out. The diagram is solved live with the same Kirchhoff's-laws math as the real circuit: in series the loop opens and every bulb goes dark, while in parallel only the clicked bulb's rung goes dark and the rest keep the full source voltage. Drag to pan the diagram and scroll to zoom in on individual bulbs.