The series circuit

A single loop, a single path

In a series circuit, all the components are connected one after the other along a single loop. The electric current therefore has only one possible path to follow: it flows through each component in turn.

Practical example

Imagine a traditional Christmas light string, where all the bulbs are connected in series. If a single bulb burns out or is unscrewed, the loop is broken at that point: all the other bulbs go out at the same time, even if they are working perfectly.

Effect on current

In a series circuit, the electric current is the same throughout the circuit, regardless of where it is measured. If a second bulb is added in series, each bulb generally receives less power: the bulbs often shine less brightly than when there is only one bulb.

A common pitfall to avoid

You might think that the order of the components in the circuit affects how they work: this is not the case in a simple series circuit. What really matters is that all the components are on the same, single path. The real pitfall is forgetting that a single break, wherever it occurs, shuts down the entire circuit: in a series circuit, all components are interdependent.