high importancemedium difficulty5 min

Series Combination

In a series combination, components are connected end to end in a single path for current.

In one line: Series means one road, one current.

Understand it

Since there is only one path, the same current passes through every component. The total resistance becomes the sum of individual resistances, and the supply voltage gets divided among the components. Series connection is simple, but one break stops the whole circuit.

Formula and rule

For series resistors, Rs = R1 + R2 + R3 ... and current is the same through all components.

See it worked out

Follow the example line by line, then use the same method on new questions.

Worked example

For resistors of 4 ohm, 6 ohm, and 10 ohm in series, total resistance = 4 + 6 + 10 = 20 ohm.

Method you can reuse

1Check that there is only one path.
2Add all resistances.
3State that current is the same everywhere.
4Mention that voltage divides across the components.

Sketch it in your answer

Draw a single path with resistors placed one after another, showing the same current arrow through each element.

Check yourself

Answer the question in your head before opening the answer.

Try it yourself

What happens to the current through each resistor in a series circuit?

Think first, then show answer

The current remains the same through every resistor because a series circuit has only one path for charge flow.

Common wrong answer

A common wrong answer is to say current divides equally in series.

Why it loses marks: There is no branching in a series circuit.

Don't mix this up

Students often think current divides in series, which is actually the rule for parallel branches.

Exam tip

Remember one path, same current, and added resistance in series circuits.