3.4 Lesson Plan Transformer

8/12/2019 3.4 Lesson Plan Transformer

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DAILY LESSON PLANSubject : PHYSICS

Class

Date

Time

Venue

Attendance

Topic T!eme: CHAPTE" #$%: ELECT"O&A'NETIS&

Lea(nin) Objecti*es:3.4 Analysing transformers

Lea(nin) Outcomes: A student is able to:

describe the structure and the operating principle of a simple transformer

compare and contrast a step-up and step-down transformer.

State that Vp/ Vs= p/sfor an ideal transformer

State that Vpp= Vss for an ideal transformer

!escribe the energy loses in a transformers

!escribe ways to impro"e the efficiency of a transformer

Sol"e the problems in"ol"ing transformers

P(e+(e,uisite: #. $lectromagnetic induction %. magnetic effect of a current carrying conductor-e. /o(ds: current& electric field

Peda)o).: 'onstructi"ism and demonstration

Values: (eing cooperati"e and being systematic

"e0lection:

Class:

Class:

Class:


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Lea(nin)Outcomes

Teac!e(1s Acti*ities Student 2 Acti*ities 3uestions and e4pectedans5e(s Notes

Vocabula(.

!escribe

the structureand theoperatingprinciple of asimpletransformer

EN'A'E&ENT

)he teacher greets the students.

)he teacher as*s the students torecall the lesson abouttransformer that they had learnt inform three.

A student comes to the front anddraws the basic structure of a simpletransformer.

): +ow are you,S: e are fine.

): ow want to *now whohere has good memoryretention. Anybody here candraw the basic structure of asimple transformer, leasename the structure.

0name of the structure: primarycoil& soft iron core& secondarycoil1

/i(e coil-gegelungdawai

P(ima(. coil-gegelung primer

Seconda(. coil-gegelung se*under

'ompare

and contrast astep-uptransformerand a step-downtransformer.

E6PLO"ATION#. )he teacher prepares an

acti"ity to the students.%. )he teacher discusses the

answer with the students.

)he students do the tas* in thewor*sheet.

): ow want gi"e you awor*sheet about thecomparison between a step-uptransformer and a step-downtransformer 0wor*sheet #1.lease complete the wor*sheet within 2 minutes.S: es& teacher.

Step+upt(ans0o(me(-transformer ina*nai*

Step+do5nt(ans0o(me(-transformer ina*turun


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State that

0Vp/Vs1=0p/s1for an idealtransformer.

State that

Vpp=Vss for anideal transformer

E6PLANATION

)he teacher discusses this formula.

)he teacher e5plains that power istransferred from primary coil to the primarycoil.

)he teacher discusseswith the students

): hat happens to the secondary"oltage when the secondary coil ismore than the primary coil,S: the secondary "oltage increasesaccordingly.

): )herefore we can ma*e aconclusion that the formula0Vp/Vs1=0p/s1 applies.

): hat is the 6uantity transferredfrom primary coil to the secondarycoil,S: ower.

!escribe the

energy losses in atransformer.

!escribe ways toimpro"e the efficiencyof a transformer.

ELA7O"ATION

)he teacher di"ides the students into fi"egroups.

)he teacher gi"es wor*sheet % to thestudents.

0the teacher can use the power point file

included in this module1

)he students do thetas*s.

): $"eryone please split into fi"egroups. lease do the tas*s inwor*sheet %. ou can discuss withyour friends.

Sol"e problems

in"ol"ingtransformer.

EVAL8ATION

)he teacher gi"es wor*sheet 3 to thestudents.

)he students do thetas*s.

): ow& we are going to learn how tosol"e problems. !o the e5ercises inwor*sheet 3


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)AS7-(AS$! 8$A9 - /o(9s!eet

Step-up

transformer

Step-down

transformer

Similarities

Differences

Function

Number of turns of Primary coilversus

Number of turns of Secondary

coil

Input (primary) voltage

versusOutput (secondary) voltage

Input (primary) current

versus

Output (secondary) current


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1 Consist of two terminals input and output

! "sed to moderate alternating current

/o(9s!eet 0)eacher;s answer sheet1

Step-up

transformer

Step-down

transformer

Similarities

Differences

#owers voltage

of alternating

current

$aises voltage

of alternating

current Function

Number of

turns of

primary coil is

less t%an t%at

of secondary

coil

Number of turns

of primary coil

more t%an t%at of

secondary coil

Number of turns of Primary coil

versus

Number of turns of Secondary

coil

Output voltage

larger t%an

input voltage

Output voltage

smaller t%an

input voltageInput (primary) voltage

versus

Output (secondary) voltage

Output current

larger t%an

input current

Output current

smaller t%an

input currentInput (primary) currentversus

Output (secondary) current


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or*sheet %


7/11

or*sheet % : Answer for teacher

$nergy 8osses $5planation +ow to 9educe $nergy8osses

Heatin) E00ect int!e Coils


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/o(9s!eet #

>9$ #

#. A light bulb labeled %4V #% is connected to a step-down transformer as shownin igure #. )he light bulb lights up with normal brightness. f the transformer is#??@ efficient& calculate0a1 umber of turns in the secondary coil0b1 'urrent flowing in the primary coil

!iagram %

%. igure % shows a #??@ efficient transformer with primary coil and secondarycoil S. )he secondary coil S is connected to a resistor 9. )he ratio for the numberof turns in to S is # : 2.0a1 f the input "oltage across is %.?V a.u& calculate the output "oltage across

9.0b1 f the current flowing through is 2.? A& calculate the current flowing through

the resistor 9.0c1 'alculate the "alue of 9

FI&"$' !


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!iagram 3

3. igure 3 shows a transformer with %??? turns in the primary coil and #?? turnsin the secondary coil S.0a1 'alculate the output power at the Bresistor.

0b1 f this transformer is C?@ efficient& calculate the input power.0c1 'alculate the current flowing in the primary coil.

4. A transformer which is D?@ efficient is used to do wor*. )he input "oltage is %4Vand will produce energy #C? E s-# . 'alculate the "alue of current flowing in theprimary coil.

2. A transformer that is C?@ efficient is connected to an input "oltage V a.u.0a1 f the output energy released per second is 4C? E& what is the "alue of the

electrical power supplied to this transformer ,0b1 0i1 f the current flowing in the primary coil is %.2 A& what is the input

"oltage of this transformer ,0ii1 f the current flowing in the secondary coil is #? A& what is the ratio of

number of turns in the primary coil to the number of turns in thesecondary coil ,

FI&"$'


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/o(9s!eet # : Answers

#. 0a1 2??0b1

!)

1A

%. 0a1 #? V0b1 #.? A0c1 #?

3. 0a1 %4 0b1 3? 0c1 ?.#%2 A

4. C.33 A

2. 0a1 B?? 0b1 0i1 %4? V

0ii1 2 : #

.


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lossary

ord )ransformer

!efinition )he apparatus for changing electrical force usually from one "oltageto another.

9elated ords rimary& secondary& coil& number of turns& "oltage)ypes Step-up transformer& step-down transformer.

'haracteristic Structural parts:

rimary coilF a coil of wire that is connected to a source of

alternating current which "oltage will be changed bytransformer& hence pro"iding magnetic flu5

Secondary coilF a coil of wire in which the "oltage of the

original alternating current in the primary coil is stepped up ordown& by electromagnetic induction

Soft-iron core F the primary and secondary coils are wound on

iron-core

'oils ratio:

Step-up transformerF umber of turns of secondary coil is less

than that of primary coil

Step-downF umber of turns of secondary coil is more than

that of primary coil

Sentences A step-down transformer is connected to the %4? V main powersupply& deli"ers B? att of power at %?V to a noteboo* computer.

eneralmeaning

3.4 Lesson Plan Transformer

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