How to Increase Brightness of Bulbs in a Circuit

When a second identical bulb is added in parallel to a single-load series circuit, both bulbs will be brighter than the original bulb.

Explanation:

In a series circuit, the current passing through each bulb is the same. When a second identical bulb is added in parallel, the total resistance of the circuit decreases because resistors in parallel have an equivalent resistance less than each individual resistor. Therefore, the current passing through each bulb increases. As a result, both bulbs will be brighter than the first one was.

So, if you want to increase the brightness of bulbs in a circuit, consider adding identical bulbs in parallel to the existing bulbs.