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Series circuit, Meaning (SPM Physics)

A circuit in which components are connected end to end in a single path, so the same current flows through each.

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EnglishSeries circuit
Bahasa MelayuLitar bersiri
中文串联电路

Definition

A circuit in which components are connected end to end in a single path, so the same current flows through each.

Electricity

In exam terms

A series circuit connects components end to end in a single loop, so there is only one path for the current. This gives three key features: the same current flows through every component; the total potential difference is shared among the components (V = V₁ + V₂ + …); and the effective resistance is the sum of the individual resistances, R = R₁ + R₂ + …, in ohms (Ω).

Example of correct use: two resistors of 3 Ω and 5 Ω in series give an effective resistance of R = 3 Ω + 5 Ω = 8 Ω.

Do not confuse it with…

Do not confuse a series circuit with a parallel circuit. In series the current is the same everywhere while the potential difference is shared; in parallel the potential difference is the same across each branch while the current is shared.

Adding a resistor in series increases total resistance, whereas adding one in parallel decreases it.

In Paper 2 you may be asked to state a characteristic of a series circuit, or to calculate effective resistance; always show that current is common before summing the resistances.

Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)

Frequently asked questions

What stays the same in a series circuit?
The current is the same at every point, because there is only one path for charge to flow. The potential difference is what gets shared among the components.
What happens if one bulb blows in a series circuit?
The single path is broken, so no current flows and all the bulbs go out. This is a key disadvantage compared with a parallel arrangement.
How do I find the effective resistance?
Add the individual resistances together: R = R₁ + R₂ + … The effective resistance is always larger than the biggest single resistor.

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