Circuits · Free game
Circuit Rush
Drag resistors into the loop until the needle sits in the green band, then close the switch.
Drag a resistor into the loop — or tap it: bin → in line → side by side.
How the physics works
Resistors in line carry the same current, so their oppositions add. More in line always means less current.
Resistors side by side each open another path, so the pair is smaller than either one on its own — and the bigger branch takes the smaller share of the current.
Reduce the loop to one resistance — banks plus lamp — and the supply voltage fixes the one current going round it.
Brightness is a power. Double the current and the lamp must shed four times the heat, which is how a lamp blows.
The supply and the wire have no resistance and the lamp keeps a fixed R. A real filament heats up, so it is not ohmic.
100 a bench, up to 60 for landing dead on, 15 per unused part, 25 per first-try streak step, less 20 per bad switch.
22.4 Resistance & Ohm’s Law22.6 Series & Parallel22.7 Electric Power