Why Are Bulbs Brighter in a Parallel Circuit

Two light bulbs on the same series circuit

Why do bulbs not dim in a parallel circuit?

In a parallel circuit the current goes through separate branches. If another branch is added with another bulb, the current has an additional path to take. But, the battery (or generator) produces a constant voltage, so the current through the original bulbs does not change, and neither does their brightness.

How do you find which bulb will glow brighter in parallel?

To find which bulb will glow brighter we need to find the power dissipation across each of them. From the relation P=(V*V)/R since voltage is same we can say that power dissipation will be higher for the bulb with lower resistance i.e. 60W bulb. Hence 60W bulb will glow brighter in parallel connection.

James H. Sterling

James H. Sterling

Environmental Science & Climate Journalist

James Sterling reports on renewable energy developments, climate policy, ecological conservation, and green tech innovations around the globe.

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