A 6-V battery powers a circuit with parallel branches on a board. Several wires and light bulbs plug into the board to make various series and parallel circuits. The brightness of the bulbs changes ...

Some of these could be replaced with a working bulb, but not all. The other type of circuit light strands use is a parallel circuit. In this setup, each bulb is on its own circuit to the power source.

The current is different in different parts of a parallel circuit. In most buildings, the lights and sockets are all connected in big circuits but you can switch individual devices off ...