Introduce to the personal computer.

Introduce to the personal computer.

1. Cases and Power Supply

   • Computer case supports internal components of the computer and also provides enclosure for added protection.
   • Case fans move air through the computer case as it passes warm component, it absorbs heat and then exits the case.
   • Computers need power supply to convert AC power from the wall socket into DC power.
   • Power supplies must provide enough power for the components that are currently installed and allow for other components that may be added at later.
   • Optical drives, hard drives, or other devices that use older technology are connected to Molex keyed.
   • Berg keyed connector connects to a floppy drive
   • SATA keyed connector connects to an optical drive or a hard drive.

2. Electricity and Ohm's law

   • Four units of electricity are-: Voltage (V), Current (I), Power (P), Resistance (R)
     • Voltage measures the work require to move form one place to another. It is measured in volts (V).
     • Current measures the amount of the elctrons moving through the circuit per second. It is measured in ampeare or amps.
     • The work required to move through a circuit is measured by power, it is multiplied the number of elctrols going through circuit per second. Power is measured in watt.
     • Resistance is the opposition of the flow of curent in a circuit measured in ohm's.
   • The formula of ohm's is voltage divided by current multiplied resistance.
     • This formula is used when two variables are unknown
   • Input device
     • Mouse and Keyboard,Touce screen, Biometric authentication device, Scanner are some of the example of input devices.
     • Mouse and Keyboard.
       • Mouse is used to guide the graphical user interface and keyboard is used to enter the text.
     • Touch screen
       • Users touch the paticular place on the screen when the computer recives instructions
     • Biometric Identification Devices
       • Biometrics guarantees that the authorized person is accessing the data.
       • Physical characteristics of the fingerprint of the user, the user is granted access if the fingerprint characteristics match the database and the correct login information is supplied.

3. Output Device

   • Printers and fax machines, Speakers and headphones are some example of output device
     • Printers and fax machines
       • Printer creates hard copies of computer files.
         • Printing colour photographs are specialize in application.
   • Speakers and Headphones
     • Speakers and Headphones are audio signals.
     • computers have audio support either integrated into the motherboard or on an adapter card.
     • Audio support has ports that allows input or output of the signals

4. Pixel -

   • Pixel is an abbreviation for picture element.
   • Pixels are the tiny dots that comprise a screen.
   • Dot pitch
     • It is the distance between pixels on the screen.
     • It gives the better image if it produce lower number.
   • They are the tiny dots that comprise a screen.

5. Contrast ratio

   • It is a measurement of the difference in intensity of light between the brightest point and the darkest point

6. Floppy Disk Drive

   • FDDs are replaced by USB flash drives, external hard drives, CDs, DVDs, and memory cards when they still have some limited uses

7. Hard Drives

   • Magnetic platters are used to store on ard drive
   • PATA, SATA, eSATA, and SCSI are the types of connector hard drive uses.
     • PATA
       • It uses a 40-pin / 80-conductor cable or a 40-pin / 40-conductor cable.
     • SATA and eSATA
       • Uese a 7-pin / 4-conductor cable
       • SATA and eSATA cables are similar, they are not interchangeable.
         • SATA are internal
         • eSATA are external
     • SCSI
       • Uses 50-pin, 68-pin, or 80-pin connector.

8. Motherboard

   • When you select a replacement motherboard, make sure that it supports the CPU, RAM, video adapter, and other adapter cards.
   • Different motherboard consist of different chipsets.
   • It consist of integrated circuits that control the communication between the CPU and the other components.

9. RAM

   • If an application is locked of or the computer frequently shows "error message" then a new RAM must be installed.
   • when buying a new RAM you must consider that it is compatible with the current motherboard

10. Adapter card

    • The alternative nae for adapter card is expansion card.