What it looks like: All components connected in a single loop — current has only ONE path to follow.
Current rule:
- Current is the SAME everywhere in the circuit
- I₁ = I₂ = I₃ = Itotal
- Think: same water flows through each section of a single pipe
Voltage rule:
- Voltages ADD UP to equal the supply voltage
- Vsupply = V₁ + V₂ + V₃
- Each component takes a "share" of the total voltage
- Bigger resistance = bigger share of voltage
Resistance rule:
- Total resistance = SUM of individual resistances
- Rtotal = R₁ + R₂ + R₃
- Adding more resistors INCREASES total resistance
Key consequence: If ONE component breaks, the WHOLE circuit stops — the loop is broken!
This deep dive covers Series Circuits — One Path Only within Series & Parallel Circuits for GCSE Physics. Revise Series & Parallel Circuits in Electricity for GCSE Physics with 20 exam-style questions and 30 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 3 of 16 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Series & Parallel Circuits
In a series circuit, what is true about the current at all points?
A student adds an extra lamp to a parallel circuit. Explain how this affects the total current from the supply and the brightness of the original lamps.