Series or parallel? Read it off the diagram

In earlier grades you saw components wired one after another, called series, and side by side, called parallel. This lesson pins that classification to the schematic itself: you will read it straight off the drawing.

Here are the same two lamps, rewired one change at a time.

These two lamps are in series, because they sit one after another on a single path.

But now the two lamps are in parallel, because each sits on its own side-by-side path.

Components sit in series when they follow one after another along a single conducting path. Components sit in parallel when each sits on its own side-by-side path.

These two lamps are still in series: a resistor between them changes nothing, because the path is still single.

This lamp and this resistor are in parallel, because each sits on its own side-by-side path.

Two resistors in parallel. The dots mark where the path splits apart and rejoins.

The split-and-rejoin drawing has two named parts. Each side-by-side path is called a branch. The points where the paths split apart and rejoin are called junctions. On the schematic, the dots where the wire divides mark the junctions.

No split between the components means series. A split and a rejoin means parallel.

A diagram shows a battery, then a resistor, then a lamp, all on one loop with no splits. Are the resistor and the lamp in series or in parallel?

There is no split: the current has a single path.

The resistor and the lamp follow one after another along it.

The resistor and the lamp are in series.

A diagram shows the wire splitting at a junction. A resistor sits on one path and a lamp on the other, and the paths rejoin. Are they in series or in parallel?

The wire splits apart and rejoins: there are two branches.

The resistor and the lamp each sit on their own branch.

The resistor and the lamp are in parallel.

Are the two resistors connected in series or in parallel?

Are the lamp and the resistor connected in series or in parallel?

Are the two lamps connected in series or in parallel?

Three more. Extra components are there to ignore: sort only the two the question names.

Are the lamp and the resistor connected in series or in parallel?

Are the two lamps connected in series or in parallel?

Are the two resistors connected in series or in parallel?

Your turn

Which two components are connected in parallel with each other?

In a parallel circuit, what are the points called where the path splits apart and rejoins?

How are the ammeter, the lamp, and the resistor connected?