SUBMITTED BY: Vishesh Srivastava SUBMITTED TO: Mr. Aditya Srivastava

I Vishesh Srivastava of Class 12th Section A Shree Devi Ahilya Shishu Vihar, Indore (M.P) Would Like to express my Sincere Gratitude to our Respected Principal Mrs. Ranjana Naik and Vice Principal Mrs. Aparna Vyas for Encouragement and help from Time to Time during my Tenure as a Student of Class 12th Section A. I also express my Sincere Gratitude towards My Physics Teacher Mr. Aditya Srivastava for helping me in completing the Project by useful Ideas and Guidelines. I thank him for encouraging me throughout and helping in all possible ways. I would also like to express my hearty gratitude to the lab assistant Mrs. Sonal Neema for their support in completion of the project. I also thank my parents and friends for their vital support and also for Encouragement and Motivation given to me for the completion of the project. Date of Submission: Vishesh Srivastava

This is to certify that Vishesh Srivastava of class 12th Section A has Worked on the Physics Project entitled “To investigate the relation between the ratio of (i) Input and output voltage, (ii)Number of turnings in the secondary coil and primary coil of a self made transformer”. He has put on his sincere efforts to collect the reading materials and has devoted sufficient periods of Practical laboratory work to complete this project. This project may be considered as Practical fulfilment of All India Senior School Certificate Exam (AISSCE) 2016-2017 conducted by CBSE.

Teachers’ signature Principal’s Signature

External Examiner’s Signature

To investigate the relation between the ratio of – 1. Input and output voltage. 2. Number of turnings in the secondary coil and primary coil of a self made transformer

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Aim Introduction Types Of Transformers Theory And Mathematical Derivations Simple Circuit Diagram Circuit Diagrams Of Step-up and Step-Down Transformers Apparatus Required to make our Own Transformer Uses of Transformers Bibliography

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The transformer is a device used for converting a low alternating voltage to a high alternating voltage or vice-versa. A Transformer based on the Principle of mutual induction according to this principle, the amount of magnetic flux linked with a coil changing, an e.m.f is induced in the neighboring coil. A transformer is an electrical device which is used for changing the A.C. voltages. A transformer is most widely used device in both low and high current circuit. As such transformers are built in an amazing strength of sizes. In electronic, measurement and control circuits, transformer size may be so small that it weight only a few tens of grams where as in high voltage power circuits, it may weight hundred of tones.

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A transformer which increases the voltages.

A transformer which decreases the A.C. voltages.

When an altering e.m.f. is supplied to the primary coil p1p2, an alternating current starts falling in it. The altering current in the primary produces a changing magnetic flux, which induces altering voltage in the primary as well as in the secondary. In a good-transformer, whole of the magnetic flux linked with primary is also linked with the secondary, and then the induced e.m.f. induced in each turn of the secondary is equal to that induced in each turn of the primary. Thus if Ep and Es be the instantaneous values of the e.m.f.’s induced in the primary and the secondary and Np and Ns are the no. of turns of the primary secondary coils of the transformer and dф / dt = rate of change of flux in each turnoff the coil at this instant, we have Ep = -Np dф/dt _______________ (1) and Es = -Ns dф/dt _______________ (2) Since the above relations are true at every instant, so by dividing 2 by 1, we get Es / Ep = - Ns / Np ______________ (3) As Ep is the instantaneous value of back e.m.f induced in the primary coil p1, so the instantaneous current in primary coil is due to the difference (E – Ep ) in the instantaneous values of the applied and back e.m.f. further if Rp is the resistance o, p1p2 coil,

then the instantaneous current Ip in the primary coil is given by Ip = E – Ep / Rp E – Ep = Ip Rp Thus back e.m.f = input e.m.f Hence equation 3 can be written as Es / Ep = Es / E = output e.m.f / input e.m.f = Ns / Np = K Where K is constant, called turn on transformation ratio.

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In a step-down transformer, secondary winding than in the primary winding in the steptransformers. Thus, the voltage supplied in the secondary transformer is greater than the one supplied across the primary winding. Because of the principltransformer converts low voltage, highlow current. In other words, the voltage has been stepped up. You can find step-up transformers located near power plants that are designed to operate megawattpower plants, step-up transformers can also be used for local and smaller applications such as xabout 50,000 volts to work. Even a microsmall step-up transformer to operate.

transformer, There are many turns on the secondary winding than in the primary winding in the steptransformers. Thus, the voltage supplied in the secondary transformer is greater than the one supplied across the primary winding. Because of the principle of conservation of energy, the transformer converts low voltage, high-current to high voltagelow current. In other words, the voltage has been stepped up.

up transformers located near power plants that are designed to operate megawatts of power. Apart from the

up transformers can also be used for local and smaller applications such as x-ray machine which requires about 50,000 volts to work. Even a micro-wave oven requires a up transformer to operate.

There are many turns on the secondary winding than in the primary winding in the step-up transformers. Thus, the voltage supplied in the secondary transformer is greater than the one supplied across the primary

e of conservation of energy, the current to high voltage-

low current. In other words, the voltage has been stepped up. up transformers located near power plants

s of power. Apart from the up transformers can also be used for local

ray machine which requires wave oven requires a

In a step-down transformer is one who secondary windings are fewer than the primary windings. In other words, the transformer’s secondary voltage is less than the primary voltage. So, the transformer is designed to convert hilow-current power into a lowis mainly used in domestic consumption. A common case of step-down application is in the case of door bells. Normally, door bells use 16 volts, but most household power circuits carry 110-120 volts. Therefore, the doorbell’s steptransformer receives the 110 volts and reduces it to lower voltage before supplying it to the doorbell. Step-down transformers are mostly used to convert the 220 volts electricity to the 110 volts re

down transformer is one who secondary windings are fewer than the primary windings. In other words, the transformer’s secondary voltage is less than the primary voltage. So, the transformer is designed to convert hi

current power into a low-voltage, high current power and it is mainly used in domestic consumption.

down application is in the case of door bells. Normally, door bells use 16 volts, but most household power

120 volts. Therefore, the doorbell’s steptransformer receives the 110 volts and reduces it to lower voltage before supplying it to the doorbell.

down transformers are mostly used to convert the 220 volts electricity to the 110 volts required in most domestic equipment

down transformer is one who secondary windings are fewer than the primary windings. In other words, the transformer’s secondary voltage is less than the primary voltage. So, the transformer is designed to convert high-voltage,

voltage, high current power and it

down application is in the case of door bells. Normally, door bells use 16 volts, but most household power

120 volts. Therefore, the doorbell’s step-down transformer receives the 110 volts and reduces it to lower

down transformers are mostly used to convert the 220 volts quired in most domestic equipment.

Iron Rod Copper Wire Hot Wire Ammeter Hot Wire Voltmeter

Take thick iron rod and cover it with a thick paper and wind a large number of turns of thin Cu wire on thick paper (say 60). This constitutes primary coil of the transformer.

Cover the primary coil with a sheet of paper and wound relatively smaller number of turns (say 20) of thick copper wire on it. This constitutes the secondary coil. It is a step down transformer.

Connect p1, p2 to A.C main and measure the input voltage and current using A.C voltmeter and ammeter respectively.

Similarly, measure the output voltage and current through s1and s2.

Now connect s1and s2to A.C main and again measure voltage and current through primary and secondary coil of step up transformer.

Repeat all steps for other self made transformers by changing number of turns in primary and secondary coil.

In voltage regulator for T.V., refrigerator, computer, air conditioner, etc.

A step down transformer is used for welding purposes.

A step down transformer is used for obtaining large current.

A step up transformer is used for the production of Xand NEON advertisement.

Transformers are used in voltage regulators and spower supplies.

Transformers are used in the transmissiodistances:

Small transformers are used in Radio sets, telephones, loud speakers and electric bells etc

In voltage regulator for T.V., refrigerator, computer, air

A step down transformer is used for welding purposes.

A step down transformer is used for obtaining large

A step up transformer is used for the production of Xand NEON advertisement.

Transformers are used in voltage regulators and s

Transformers are used in the transmissions of a.c. over long

Small transformers are used in Radio sets, telephones, loud speakers and electric bells etc.

In voltage regulator for T.V., refrigerator, computer, air

A step down transformer is used for welding purposes.

A step down transformer is used for obtaining large

A step up transformer is used for the production of X-Rays

Transformers are used in voltage regulators and stabilized

ns of a.c. over long

Small transformers are used in Radio sets, telephones, loud

www.google.com www.wikipedia.org Physics NCERT Pradeep’s Physics

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