Does the same current pass through each bulb in a parallel circuit?

1 Answer
Jan 24, 2018

No, the magnitude of the current going through each bulb would be, at least slightly, different.


To keep the discussion simple, assume we are talking about 2 bulbs wired in parallel. Even if both bulbs came from the same package of bulbs (therefore same wattage) there would be a slight difference between the results of a careful measurement of resistance of the 2 bulbs. They would be within a few % of the same resistance, but not 100% identical. There would be no reason for the manufacturer to provide 100% consistent resistance values.

Ohm's Law says that #I = V/R#. The voltage across each bulb may also slightly different because of different resistance in the wires going to each bulb. So no, both the voltage across each bulb and the individual bulb's resistance would vary slightly, therefore the magnitude of the current in the 2 parallel paths would not be identical. Close, but not identical. Perhaps in a perfect world, they would be identical values.

Perhaps by "same current" you mean the actual same electrons. When the electrons in the wire come to the point where the 2 parallel paths separate, each electron has to decide which path to take. In a parallel circuit no electron goes through both bulbs.

If the 2 bulbs were wired in series instead, then the current in the 2 bulbs would not have a choice. Each electron must pass through both (unless a few of them do not make it to the 2nd bulb before someone turns the switch off).

I hope this helps,