IGCSE 0625 / Section 4.3.2 / Core

Many paths, shared push.

Give the current more than one branch to flow through and it splits, taking each road at once. Every branch feels the full push of the supply, which is why the lights in a house all run at full brightness.

The key idea

In a parallel circuit each branch has the full supply voltage across it. The current from the source splits between the branches and the branch currents add to the total. Adding parallel branches lowers the combined resistance below that of any single branch.

Definition · learn the exact words

In a parallel circuit the components are on separate branches across the supply. Each branch has the full supply voltage, the branch currents add to the total, and the combined resistance is less than the smallest branch.

at a junction: current in = current out

Adding a parallel branch lowers the combined resistance.

Section 01

Split the current.

Add branches and watch the current divide while each branch keeps the full voltage.

Stage 1 · Learn

Check parallel

Four quick checks. Each correct answer earns XP and lights this skill on your star map.

Quick check+10 XP

In a parallel circuit, the voltage across each branch is...

Quick check+10 XP

The total current from the supply equals...

Quick check+10 XP

Adding another branch in parallel makes the combined resistance...

Quick check+10 XP

At a junction, the current flowing in...

Section 02

Shared voltage, divided current.

The voltage is the same across each branch, and the branch currents add up to the supply current.

Examiner trap

In parallel each branch gets the full supply voltage, the voltage is not shared. The branch currents add to the total, and the combined resistance is less than the smallest single resistor, not more.

Stage 2 · Exam

Exam-style questions

Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.

Finish the four checks above to unlock the exam questions
Exam style+20 XP

A current of 0.60 A reaches a junction and 0.40 A flows down one branch. The current in the other branch is...

Exam style+20 XP

Two 6.0 Ω resistors are connected in parallel. Their combined resistance is...

Exam style+20 XP

Two lamps are connected in parallel across a 12 V supply. The voltage across each lamp is...

Skill unlocked

Parallel, mastered.

Parallel circuits are mapped. Keep the chain going.

-Rank -Level -Score -Topics
Go deeper · practice
Six original Cambridge-style questions
Voltage, current and combined resistance in a parallel circuit and the junction rule. Attempt each, then reveal the worked solution.
Stage 3 · master the unit
Electricity and magnetism challenge
Mixed questions across the whole unit, each one worth XP. Start this only when you feel confident across every topic in the unit, not just parallel.
Start the unit challenge →