Circuit BuilderSt Peter's Science Portal
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Electricity

Build & Measure a Circuit

Drag a cell and resistors onto the board, then drag from one terminal to another to wire them up. Adjust each resistance, and click a resistor to read the current and voltage through it. The circuit is solved live, so series, parallel, and combined networks all work.

Parts

Cell
Resistor
Switch

Resistor

Current
Voltage
Power dissipated
Drag a cell and some resistors onto the board to begin.
Quiz mode

How it works

Every resistor obeys Ohm's law, V = IR. When you wire components together the board solves the whole network at once using nodal analysis — it finds the voltage at every junction, then works out the current in each branch. That means it handles series chains, parallel branches, and any combination of the two, not just simple cases. Click any resistor to see the current flowing through it and the voltage across it; adjust its resistance and watch the whole circuit respond. A complete loop from one battery terminal back to the other is needed for any current to flow.