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Circuit
Series
Total current
0.75 A
Voltage per bulb
3.0 V
Power per bulb
2.25 W
How to use: Two identical bulbs run off one battery.
Start in series — the bulbs share the voltage, so each gets half.
Click Switch to parallel and each bulb spans the full battery by itself,
so the current through each one doubles and they glow much brighter. Try changing
the voltage and resistance in both arrangements and compare the numbers.
Notice: in series the voltage is shared (each bulb gets half the battery),
so the power per bulb is a quarter of the parallel value. In parallel the voltage is
the same across each bulb, so each glows at full brightness — but the battery
now supplies double the current. That's why homes are wired in parallel: every
appliance gets the mains voltage.