Circuit Builder
A real circuit-building sandbox: place batteries, resistors, switches, and LEDs on a grid and wire them together. Every current and voltage shown is computed by actually solving the circuit, not looked up from a template - build a series loop, then a parallel branch, and compare.
Add a battery to power the circuit.
Readouts
How To Use It
Pick a tool above, then click any grid line to place it there.
Click a placed resistor or battery to cycle its value, or double-click it to type an exact one.
Click a switch to open or close it — click and drag it to flip which way it swings.
Place an Ammeter in series to read current, or a Voltmeter across two points to read voltage.
Use Fullscreen for a bigger workspace, and Erase to remove anything.
Every value shown is computed by actually solving the circuit’s node voltages — try building a series loop, then a parallel branch, and compare.