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Presented by:-Presented by:-

NAME : Sanjay Kumar Pani BRANCH : Electrical & Electronics GROUP : ‘B1’ ROLL NO. : E/04/14

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CONTENTS1. Introduction

2. A Typical linear Power Supply.

3. Working Of SMPS.

4. Capacity Of Power Supply.

5. Power Supply PC.

6. The Computer Supply’s Duties.

7. Power Supply Improvement.

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INTRODUCTION:-INTRODUCTION:- A Power supply is the heart of computer A Power supply is the heart of computer

system. The power supply system. The power supply converts alternating converts alternating current (AC) line from your direct current current (AC) line from your direct current (DC)(DC) needed by the personal computer. needed by the personal computer.

A computer needs a well regulated A computer needs a well regulated 5 volt5 volt and and 12 volt DC12 volt DC power supply for the proper power supply for the proper functioning of its various parts. Without a functioning of its various parts. Without a good and proper power supply the computer good and proper power supply the computer can not do work.can not do work.

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AS shown fig-1, a power supply is used in between the AS shown fig-1, a power supply is used in between the computer and mains to computer and mains to convertconvert the the 240v AC240v AC current current to ato a well regulated well regulated 12 volt and 5 volt DC current12 volt and 5 volt DC current..

Usually, the electronic components and circuits in the Usually, the electronic components and circuits in the system (system (Motherboards, Adapter cards and Disk drive logic Motherboards, Adapter cards and Disk drive logic boardsboards etc.) use the 5 volt & etc.) use the 5 volt & Motors in the disk drive and Motors in the disk drive and the hard diskthe hard disk use 12 volt respectively use 12 volt respectively

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The main specification of power supply is in The main specification of power supply is in wattswatts. . A watt is the product of volts and current in A watt is the product of volts and current in amperes.amperes.

Today we turn on the power with a little push Today we turn on the power with a little push button &turn off machine with menu option.button &turn off machine with menu option.

A Typical Linear Power Supply:-A Typical Linear Power Supply:- The basic components of a typical The basic components of a typical

linear power supply are shown in fig-2.linear power supply are shown in fig-2.

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This power supply contains a This power supply contains a transformer, transformer, rectifier, capacitor, and regulatorrectifier, capacitor, and regulator..

Disadvantages:Disadvantages: The main disadvantages of linear The main disadvantages of linear power supply are its power supply are its large and poor efficiencylarge and poor efficiency..

Because, the computer system use a Because, the computer system use a completely different type of power supply, which is completely different type of power supply, which is called as called as SMPS or Switch Mode Power SupplySMPS or Switch Mode Power Supply..

Advantages:Advantages: The main advantages of SMPS as the The main advantages of SMPS as the power supply is it power supply is it reduced size, less cost, high reduced size, less cost, high efficiencyefficiency..

The main difference between the linear power The main difference between the linear power supply & switch mode power supply is the way the supply & switch mode power supply is the way the output voltage is generated and regulatedoutput voltage is generated and regulated..

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Working of SMPS:-Working of SMPS:- In a In a SMPSSMPS, the mains , the mains AC supplyAC supply is first send is first send

to a to a rectifier/filter unitrectifier/filter unit, which , which convertsconverts the Ac the Ac supply into supply into very high value, DC voltage. very high value, DC voltage.

The high voltage DC supply is given to The high voltage DC supply is given to

switching transistor circuit. The switching switching transistor circuit. The switching transistor circuit switches the given high transistor circuit switches the given high voltage DC voltage DC on & offon & off at the same frequency. at the same frequency. The voltage at secondary winding is then The voltage at secondary winding is then rectified and filtered to produce the rectified rectified and filtered to produce the rectified outputoutput..

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Capacity of Power Supply:-Capacity of Power Supply:- The capacity of a power supply is measured in The capacity of a power supply is measured in

watt or kilo wattwatt or kilo watt. Watt is the unit of amount of the . Watt is the unit of amount of the work done by the electricity. So that all the parts work done by the electricity. So that all the parts of the computer such as: of the computer such as: RAM, Motherboard, RAM, Motherboard, DrivesDrives etc. etc.

Power Supply of PC:-Power Supply of PC:- A PC contains many electronic components such A PC contains many electronic components such

as: as: a lot of memory, adapter cards, hard diska lot of memory, adapter cards, hard disk etc. etc. it requires high quality power.it requires high quality power.

Modern SMPS power supplies used in computers are Modern SMPS power supplies used in computers are small and efficient and also equipped with a fan for small and efficient and also equipped with a fan for cooling purpose.cooling purpose.

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The The back of the power supplyback of the power supply contains contains fourfour things. things. They areThey are

The computer’s power connector.The computer’s power connector. The monitor’s power connectorThe monitor’s power connector The fan exhaust portThe fan exhaust port A power switchA power switch

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The computer power supply’s duties:The computer power supply’s duties: The power supply has The power supply has 3 main3 main duties. duties.

They areThey are It supplies PC with power.It supplies PC with power. It cools the system.It cools the system. It protects the internal componentsIt protects the internal components..Power Supply Improvement:-Power Supply Improvement:- Some new computers, particularly those Some new computers, particularly those

designed for use as servers, provide redundant power designed for use as servers, provide redundant power supplies. This means there are two or more power supplies. This means there are two or more power supplies in this system, with one providing power and supplies in this system, with one providing power and other acting backup.other acting backup.

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