The system unit, or computer case, houses the main internal components of a computer including the motherboard, central processing unit (CPU), random access memory (RAM), power supply, hard disk drive, optical disk drive, and expansion cards. The power supply provides power to these components by converting alternating current from wall outlets to direct current and regulating voltage. The motherboard acts as the foundation and allows the CPU, RAM, and other components to communicate. It allocates power and contains connections for attaching these internal parts.

1. System Unit

2. SYSTEMUNIT
• One of the basic components of acomputer which
contains all of the main parts of it.
• It houses the internal components of the computer
such us motherboard, CPU,RAMand
others.

3. PARTSOFA
SYTEMUNIT

4. POWERSUPPLY(PowerSupplyUnit/PSU)
• The component that supplies power to a
computer.
• Most personal computers can be plugged into
standard electrical outlets. The power supply
then pulls the required amount of electricity
and converts the AC current to DC current.

5. POWERSUPPLY(PowerSupplyUnit/PSU)
• The component that suppliespower to a computer.
• Most personal computers can be plugged into
standard electrical outlets. The power supply then
pulls the required amount of electricity and converts
the AC current to DC current.
• It regulates the voltage to eliminate spikes and surges
common in most electrical systems.

6. • 20 ATXpin connector - connects the power supply to a particular
motherboard. ATX motherboards are attached with 20 or 24 pin
connectors.
• CPU connector - used to connect power supplies to motherboards
with on board computer processing units (CPUs). These are either
4 ("P4") or 8 pin connectors.
• Molex connector - the IDEconnector that connects to hard drives
and CDROM drives. Most computer power supplies include at
least one of these connectors.
• Floppy connector - 4 pin connector used to supply power to
floppy drives, card reader drives, and other similar devices.
• AUX connector - a 6 pin connector that is a necessary connection
for some computer motherboards.
• SA
TAconnector - connectors for devices using serial advanced
technology attachment (SATA) interfaces, such as hard drives.
• PCIexpressconnector - used to connect to PCIexpress video
cards, which receive power directly from the power supply rather
than from the motherboard.

7. OPTICALDISKDRIVE (CDor DVD
ROM/ODD)
• A device that usesphoto
diodes to detect reflecting lights
on optic discs.
• A CD drive is a device used
with a computer to read or
write a compact disc.s

8. FLOPPYDISKDRIVE
• A disk drive that can read
and write to floppy disks.
• A computer disk drive
that enables a user to
save data to removable
diskettes.

9. HARDDISKDRIVE (Hard Drive/HDD)
• Main storage device used to store all
the data permanently.
• Commonly, hard drives are
permanently paced in an internal
drive bay at the front of the system
case. But nowadays, there are
portable which use USBports and
cables for connection.

10. INTEGRATEDDRIVE
ELECTRONICS(IDE)
• Generally, it refers to the types
of cables and ports used to
connect some hard drives and
optical drives to each other
and to the motherboard.
• SATA - Serial Advanced
Technology Attachment

11. RANDOM ACCESSMEMORY(RAM)
• a computing device where the
operating system (OS), application
programs and data in current use are
kept so they can be quickly reached
by the device's processor.
• Random Access Memory is volatile.
That means data is retained in RAM
as long as the computer is on, but it is
lost when the computer is turned off.

12. • Often referred to as the brain of the computer.
• Electronic machinery that carries out instructions from
hardware and programs that allows a computer or
other device to perform its tasks
CENTRALPROCESSINGUNIT (CPU)

13. • An expansion card is an electronic
card/board that is used to add
extra functionality to a computer.
• An expansion card is used to
give a computer additional
capabilities, such asenhanced
video performance via a
graphics card.
EXPANSIONCARD(Add-on or Interface Card)

14. VIDEO CARD(GraphicsCard/Display Adapter)
A hard component use to generate and display
the output images to a computer monitor.

15. MOTHERBOARD
• A printed circuit board that is the
foundation of a computer, located at
the bottom of the computer case.
• It allocates power to the CPU,RAM,
and all other computer hardware
components. Most importantly, the
motherboard allowshardware
components to communicate with
one another.

16. CPUSOCKET
• Holds the CPU
• All connected to the motherboard.
MEMORY SLOT
• Allows computer memory (RAM) to
be inserted into the computer
• There may be 2 to 4 memory slots.

17. CPUFAN AND HEAT SINK
An electronic device that to
keep the processor cool

18. BACKPANEL
The portion of the motherboard that allowsyouto
connect external devicessuchasyour monitor,
speakers,keyboard, mouseand others.