Parallel Circuits

This lesson covers:

  1. What a parallel circuit is
  2. How parallel circuits affect potential difference, current, and resistance
Diagram comparing series and parallel circuits with labelled circuit A and circuit B.

Which of these circuits is series, and which is parallel?

A is parallel and B is series

A is series and B is parallel

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Diagram of a parallel circuit with one blown filament lamp and two functioning lamps.

In the parallel circuit above, one of the filament lamps has blown and broken that part of the circuit.


In this scenario the other two lamps will:

Stay on

Turn off

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All the components in a parallel circuit have the same potential difference.

Diagram of parallel circuit with filament lamps A and B and a 9V battery.

The filament lamps A and B are in parallel.


The potential difference across filament lamp A is V.


The potential difference across filament lamp B is V.

9
9

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Diagram showing a parallel circuit with current distribution, where the total current is 5A, and the current in each parallel loop is 2A and 3A respectively.

equal / shared / sum


The total current is between all of the parallel loops.


The of the current in each loop is equal to the total current.

shared
sum

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Diagram of a parallel circuit showing total current of 6A and 1A flowing through the bottom filament lamp.

The above diagram shows a parallel circuit.


The total current is 6 A, and 1 A is flowing through the bottom filament lamp.


What is the current flowing through the top filament lamp?

5

A

A

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Adding a resistor in parallel with an existing resistor will ________ the overall resistance.

decrease

increase

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