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Chapter 2 Power Supply

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Chapter 2 Power Supply

1. 1. DIT 411 PC HARDWARE 1 CHAPTER 2: POWER SUPPLY AND COMPUTER CASE
2. 2. BASICS OF ELECTRICITY <ul><li>Electricity is a basic part of nature and it is one of our most widely used forms of energy. </li></ul><ul><li>Electricity is about charge . Charge is a property of electrons and protons which are part of an atom . Electrons have negative charge and are mobile because they have 1/1830 of the mass of the positive proton. </li></ul><ul><li>Neutrons have the same mass as a proton , but no any charge. </li></ul>
3. 4. Electron <ul><li>Electron in motion is called electric current which we use every day in our homes . In other words, Electricity is simply a flow of negative charged particles, called electrons through conductors like copper wire. </li></ul><ul><li>In most metals, the nuclei of atoms (protons & neutrons) are bonded together. </li></ul><ul><li>The pressure the electrons in the wire is called voltage and is measured in units called volts (V) . </li></ul><ul><li>The amount of electrons moving past a certain point on a wire is called the current, which is measured in units called amperes (Amps or A). </li></ul>
4. 5. Type of electric current <ul><li>Alternating current (AC) </li></ul><ul><ul><li>electrons flow in one direction around a continuous path </li></ul></ul><ul><li>Direct current (DC) </li></ul><ul><ul><li>electrons alternates direction back and forth </li></ul></ul>
5. 6. Power Supply <ul><li>Designed to convert 110 volt or 230 volt AC power from the mains to usable low-voltage DC power (12 volt, 5 volt and 3.3volt) for the internal components of the computer. </li></ul><ul><li>It provides the necessary electrical power to make the computer work. A power supply is rated by the number of watts it generates. </li></ul><ul><li>Because motherboards, power supplies and computer cases are often sold together and must be compatible with each other. </li></ul><ul><li>Personal Computer (PC) power supply consists of single box with lots of wires coming out of it to connect various internal components and motherboard of a computer. </li></ul><ul><li>Understanding power supply units of a PC is very important because any problem in power supply can crash your computer and can corrupt your valuable information (data). </li></ul>
6. 7. <ul><li>Power Supply In a personal computer (PC), the power supply is the metal box usually found in a corner of the case. The power supply is visible from the back of many systems because it contains the power-cord receptacle and the cooling fan </li></ul>
7. 9. The interior of a power supply.
8. 10. WARNING: Do not open the power supply, it contains capacitors which can hold Electricity (WHICH CAN KILL) even if the computer is power off for a week, if not longer
9. 11. Power Supply Form Factors <ul><li>Form Factor : industry term for the size, shape, type and external connector. </li></ul><ul><li>There are approximately eight industry standard </li></ul><ul><li>Form factors for power supplies. They are: </li></ul><ul><li>Personal Computer / Extended Technology (PC/XT) </li></ul><ul><li>Advanced Technology (AT) Desktop type </li></ul><ul><li>AT Tower Type </li></ul><ul><li>Baby AT </li></ul><ul><li>LPX </li></ul><ul><li>Advanced Technology Extended (ATX)/NLX </li></ul><ul><li>SFX </li></ul><ul><li>WTX </li></ul>
10. 12. Power Supply Form Factors – PC/XT <ul><li>first used in IBM desktop in 1983. </li></ul><ul><li>Called as extended technology. </li></ul><ul><li>placed into the rear of the case – right hand side </li></ul><ul><li>controlled by an up/down toggle switch </li></ul>
11. 13. Power Supply Form Factors – AT (Desk Type) <ul><li>“ AT” – advanced technology </li></ul><ul><li>introduced by IBM in 1984 </li></ul><ul><li>increased in size. </li></ul><ul><li>The original AT power supply provided 192 Watts , </li></ul>
12. 14. Power Supply Form Factors –AT (Tower) <ul><li>Introduce tower style cases </li></ul><ul><li>Introduced the first remote power switch. </li></ul><ul><li>The control wires for the switch were passed through the same hole in the front of the power supply case that was used for the motherboard and drive connector bundle. </li></ul>
13. 15. Older AT Style Power Supply
14. 16. Power Supply Form Factors – BABY - AT <ul><li>smaller version of the original AT form. </li></ul><ul><li>It has the same height and </li></ul><ul><li>length, but is about 2&quot; less in width. </li></ul><ul><li>It has the same motherboard connectors and drive connectors as the AT </li></ul><ul><li>introduced around the time PCs began to grow. </li></ul><ul><li>The Baby AT power supply was made in both a tower and desktop configuration, </li></ul><ul><li>the most popular design over a decade. </li></ul>
15. 18. Power Supply Form Factors – LPX <ul><li>The LP in LPX stands for low profile . </li></ul><ul><li>They are also often called slimline power supplies because LPX cases are often called slimline cases . </li></ul><ul><li>size reduction. The height in particular of the power supply is significantly reduced, facilitating the design of much smaller, consumer-oriented PCs. </li></ul><ul><li>The connectors of the LPX form factor power supply are the same as that of any AT families. </li></ul><ul><li>use remote power switches. </li></ul><ul><li>made in large quantity and millions of these power supplies are still in use. </li></ul>
16. 20. Power Supply Form Factors – ATX/NLX <ul><li>Introduction by Intel in 1995 . </li></ul><ul><li>The Advanced Technology Extended (ATX) form factor was the most significant change in system design </li></ul><ul><li>Now standard in the marketplace. </li></ul><ul><li>The NLX motherboard and case form factor designed to replace LPX. </li></ul><ul><li>The ATX power supply appears virtually identical to an LPX power supply in terms of its dimensions and component placement. </li></ul>
17. 21. <ul><li>The ATX power supply design consist: </li></ul><ul><li>True Standard </li></ul><ul><li>Soft Power </li></ul><ul><li>Additional Signals </li></ul><ul><li>Changed Motherboard Connectors </li></ul><ul><li>Modified Fan Direction and Placement </li></ul>
18. 22. Power Supply Form Factors – ATX/NLX Rear view
19. 23. Power Supply Form Factors – SFX <ul><li>In 1997 Intel introduced the new microATX form factor, based upon the original ATX form factor. </li></ul><ul><li>In 1999, Intel produced the FlexATX addition to the microATX specification, detailing plans for an even smaller motherboard and case standard. </li></ul><ul><li>Later, Intel created the SFX power supply form factor, which they may optionally use. </li></ul><ul><li>“ S” stand for small </li></ul><ul><li>The specified output rating of the SFX power supply is 90 W. This is sufficient to run rather small systems with low-powered CPUs and few peripherals </li></ul>
20. 24. View of the top and side of an SFX power supply, showing the top-mounted cooling fan.
21. 25. Power Supply Form Factors – WTX <ul><li>WTX was introduced by Intel in 1998 , and revised in 1999. </li></ul><ul><li>designed specifically for workstations. W in WTX stands for Workstation. </li></ul><ul><li>WTX defines a standard for motherboards, cases, and power supplies. </li></ul><ul><li>It is designed in a modular way from the ground up to allow it to meet the needs of large, multiple-CPU systems now and in the future . </li></ul>
22. 26. <ul><li>The motherboard is mounted on a special mounting plate </li></ul><ul><li>which gives motherboard makers the flexibility to design boards </li></ul><ul><li>suit the needs of larger system </li></ul><ul><li>supplies large power </li></ul>
23. 27. AT POWER SUPPLY CONNECTORS <ul><li>Industry standard PC/XT, AT, Baby AT, and LPX motherboards all use the same type of main power supply connectors. These supplies feature two main power connectors (P8 and </li></ul><ul><li>P9) , each with 6 pins that attach the power supply to the motherboard. </li></ul>
24. 29. ATX POWER SUPPLY CONNECTOR <ul><li>Modern motherboard uses a 20 or 24 pin P1 power connector . Some motherboards may require special 4-, 6- or 8-pin connectors to supply extra power . The ATX, NLX and SFX power supplies have 20-pin connectors that attach to the motherboard. </li></ul>
25. 30. Power Supply Connections to Peripheral Hardware - MOLEX <ul><li>the most commonly used </li></ul><ul><li>provides both 12 volt and 5 volt </li></ul><ul><li>hard disk drives, CD Rom drives </li></ul>
26. 31. Power Supply Connectors to Peripheral Hardware - Mini Connectors <ul><li>supply power to floppy drive </li></ul><ul><li>standard connector for 3.5 inch floppy disk </li></ul><ul><li>four pins out and usually four wires </li></ul>
27. 32. Power Supply Connectors - SATA Connectors <ul><li>Serial Advanced Technology Attachment (SATA) designed for transfer data to and from hard disks and optical drives. </li></ul><ul><li>SATA hard drives </li></ul><ul><li>need a special 15 pin SATA power connector . </li></ul>
28. 33. Power Supply Connectors - Splitters <ul><li>using splitters to create more connections </li></ul>
29. 34. Power Supply Connectors - Mini Adapter <ul><li>most systems come with a single mini connector </li></ul><ul><li>for an additional mini connector use mini adapter </li></ul>
30. 35. Computer Cases <ul><li>Usually made of metals </li></ul><ul><li>Holds all the primary electronics </li></ul><ul><li>Three general rules to consider: </li></ul><ul><ul><li>the bigger the box, the more component it can hold </li></ul></ul><ul><ul><li>the more compact the box, the less expansion potential it has </li></ul></ul><ul><ul><li>smaller cases that come with a power supply usually have lower wattage </li></ul></ul>
31. 36. DESKTOP <ul><li>Desktop computer cases are for the models of PC that sit on the desk horizontally . </li></ul><ul><li>As far as computer cases go, desktops have the least amount of choice available on the market. </li></ul><ul><li>Although the majority of new PC's come with towers or mini towers, some are still built using desktops case. </li></ul>
32. 38. MINI TOWER
33. 39. Full Tower
34. 40. <ul><li>Following factors need to be considered while choosing a computer case: </li></ul><ul><li>Size </li></ul><ul><li>Cooling </li></ul><ul><li>Installation features </li></ul><ul><li>Power supply </li></ul><ul><li>Convenience Items </li></ul><ul><li>Style </li></ul>