Science In Pictures

Three identical light bulbs are very dimly lit in the picture on the left. When those same light bulbs were connected to the same

3 V power source, each light suddenly glows brighter. Why? On the left they are connected in series, which increases overall

resistance and lowers the current. On the right they are connected in parallel, which lowers overall resistance and increases

current. Even though the current splits three-ways, each parallel branch receives more current than the series circuit.

Not convinced?

Suppose that each light bulb in series had a resistance of 1 W. That would create a total resistance of 3 W and a constant

current of 3V/3 W = 1 A. But in parallel those same bulbs would have an overall resistance of only [1^-1 + 1^-1 + 1^-1]^-1

= 0.33 W, with an overall current of 3V/0.3 W = 9A, which means that each bulb would receive triple the current

of the series circuit!