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ElectricityElectricityElectricityElectricity: : : : Various circuitsVarious circuitsVarious circuitsVarious circuits IntroductionIntroductionIntroductionIntroduction: : : :

Last topic, we learned how to light with one bulb one bulb one bulb one bulb and one power cellone power cellone power cellone power cell....

This topic we are going to

learn about complex circuits

as shown left.

SubSubSubSub----topic: topic: topic: topic: series and parallel circuitseries and parallel circuitseries and parallel circuitseries and parallel circuit

1. Make idea to light two bulbs, and identify each bulb light or not

ExperimentExperimentExperimentExperiment 1 1 1 1 LLLLight two bulbs in a circuitight two bulbs in a circuitight two bulbs in a circuitight two bulbs in a circuit

Dry cell

Bulb ×2 MATERIALS

ConclusionConclusionConclusionConclusion

� TTTThere are two way to light two bulbs in a circuit.here are two way to light two bulbs in a circuit.here are two way to light two bulbs in a circuit.here are two way to light two bulbs in a circuit.

1.1.1.1. Two bulbs are connected in single lineTwo bulbs are connected in single lineTwo bulbs are connected in single lineTwo bulbs are connected in single line

2.2.2.2. EEEEach bulbs are connected in each lineach bulbs are connected in each lineach bulbs are connected in each lineach bulbs are connected in each line

QQQQuestion 1 uestion 1 uestion 1 uestion 1

How do you light two bulbs ?How do you light two bulbs ?How do you light two bulbs ?How do you light two bulbs ?

Connect Result

Two bulbs are connected in single line

Each bulb are connected in each line

Single line

2

I think one of bulbs in series

circuit is dimmer than a bulb in

simple circuit

I think one of bulbs in parallel

circuit is still bright as same as a

bulb in simple circuit

IIII you compare bulbs connected in series andyou compare bulbs connected in series andyou compare bulbs connected in series andyou compare bulbs connected in series and parallel, how parallel, how parallel, how parallel, how different is the different is the different is the different is the

brightness of each bulb?brightness of each bulb?brightness of each bulb?brightness of each bulb?

Remind last experiment

Series circuit and parallel circuitSeries circuit and parallel circuitSeries circuit and parallel circuitSeries circuit and parallel circuit

Single path

Multiple paths

Parallel circuitParallel circuitParallel circuitParallel circuit

Two bulbs connected in seriesTwo bulbs connected in seriesTwo bulbs connected in seriesTwo bulbs connected in series Two bulbs connected in parallelTwo bulbs connected in parallelTwo bulbs connected in parallelTwo bulbs connected in parallel

Series circuitSeries circuitSeries circuitSeries circuit

ItItItIt’’’’s also parallel circuits also parallel circuits also parallel circuits also parallel circuit

A circuit has two or more blubs in single path

is called series circuitseries circuitseries circuitseries circuit.

A circuit has two or more (multiple) path of

electricity is called parallel parallel parallel parallel circuitcircuitcircuitcircuit.

And, if the path of electricity is divided into

two or more paths, it’s also called parallel

circuit.

Divided

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1. Make a simple circuit at first. Then connect one more bulb with it in series and parallel. And compare

the brightness of each bulb

ConclusionConclusionConclusionConclusion

� OOOOne of bulbs in series circuit is dimmer than a bulb in simple circuitne of bulbs in series circuit is dimmer than a bulb in simple circuitne of bulbs in series circuit is dimmer than a bulb in simple circuitne of bulbs in series circuit is dimmer than a bulb in simple circuit....

� OOOOne of bulbs in parallel circuit is still bright as same as a bulb in simple circuitne of bulbs in parallel circuit is still bright as same as a bulb in simple circuitne of bulbs in parallel circuit is still bright as same as a bulb in simple circuitne of bulbs in parallel circuit is still bright as same as a bulb in simple circuit....

ExperimentExperimentExperimentExperiment 2222 CCCCompare the brightness of eompare the brightness of eompare the brightness of eompare the brightness of each bulb in circuitsach bulb in circuitsach bulb in circuitsach bulb in circuits

Get dimmer

Still bright

Result

The number of bulbs and the brightness of bulbs

The more bulbs

connected in series, each

bulb will be the dimmer.

Although the more bulbs

connected in parallel, the

brightness of each bulb is

constant.

Parallel circuits other form Try these forms of

parallel circuits. These

are also constant.

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ExerciseExerciseExerciseExercise

1. Answer series or parallel circuit each of the following circuit.

And, choose the dimmest circuit.

a) b) c) d)

Find out the path of electricityFind out the path of electricityFind out the path of electricityFind out the path of electricity

If you want to find path of electricity, trace the

line from positive to negative.

If you find out only single path in a circuit, it is

series circuit or simple circuit.

Identify the number of blubs, and you can find

which circuit is series or simple circuit.

Two bulbs One bulb

If you find a fork, trace each line to

find out all of path. After you trace,

you can identify electricity pass from

positive terminal through each bulb

to negative terminal.

At this time, you find out two paths

(or more) of electricity. So, it is

parallel circuit.

Fork Fork

If you find two (or more) paths of electricity, it is

parallel circuit.

You can find out electricity pass from positive

terminal through each bulb to negative

terminal.

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ExperimentExperimentExperimentExperiment 3333 CCCCut series and parallel circuitut series and parallel circuitut series and parallel circuitut series and parallel circuit

QQQQuestion 3 uestion 3 uestion 3 uestion 3

If series and parallel circuit is cut down, what will be happen?

I think If I will cut one of forked

line, One of bulb will still light and

other will not light.

You can’t trace from positive to negative.

You can’t trace from positive to negative

Expectation

I think if I will cut a series

circuit, all of bulbs will die