The document discusses the components and functions of a computer system unit. It defines the system unit as the part of the computer that houses primary components like the motherboard, CPU, RAM, and case. It then lists and describes 11 key components of the system unit, including the motherboard, CPU, RAM, hard drive, fans, power supply, and video card. The objectives are to understand the system unit concept and components, and appreciate why knowing them is important.

1. COMPUTER SYSTEM
UNIT
Computer System Servicing CSS II

2. Review Lesson
◦RAM -
◦CPU -
◦ROM -
◦HDD -

4. 1. TO UNDERSTAND THE CONCEPT OF THE SYSTEM UNIT,
ITS BASIC COMPONENTS, AND FUNCTIONS
2. TO IDENTIFY AND DESCRIBE THE BASIC COMPONENTS
OF THE SYSTEM UNIT, INCLUDING THE MOTHERBOARD,
CPU, RAM, AND OTHER PARTS OF THE SYSTEM UNIT
3. TO APPRECIATE THE IMPORTANCE OF KNOWING THE
COMPONENTS OF THE SYSTEM UNIT.
Lesson Objectives

5. Video Presentation about the lesson

6. What Does System Unit Mean?
◦A system unit is part of a computer that houses the
primary devices that perform operations and
produce results for complex calculations. It includes
the motherboard, CPU, RAM, and other
components, as well as the case in which these
devices are housed. This unit performs the majority
of the functions that a computer is required to do.

7. Components of System Unit
◦ Some of the components in the system unit are; random access
memory (RAM), compact disk read-only memory (CD-ROM), hard disk,
motherboard, fan, processor or central processing unit (CPU), power
supply, and floppy disk drive.
◦
◦ The system unit also has other components, such as a universal serial
bus (USB) port, power button, cables, video, and sound card.

8. Main components of the system unit.
◦ 1. Motherboard
◦ The motherboard is the main internal hardware component of the system unit. This board is called the
"motherboard" because it has all the connectors that connect to the other hardware components of the
computer system.

9. 2. CPU or PROCESSOR
◦ 2. CPU or Processor
◦ The CPU is the hardware component responsible for all operations performed in the computer system,
which is why most computer users call it the brain of the computer, which is fixed on the motherboard
through a slot.

10. 3. RAM
◦ 3. RAM (Random Access Memory)
◦ RAM is the main memory of a computer system, and its main function is to temporarily store data.

11. 4. Hard Drive
◦ 4. Hard Drive
◦ The main storage device of a computer system is a hard disk or hard disk drive. Unlike RAM, which
temporarily stores data, the main function of a hard drive is to permanently store information, files, and
other documents, and also allows data to be retrieved, but it is non-volatile (data will not be lost when
the computer is shut down).

12. 5. CPU Fan and Heat Sinks
◦ 5. CPU Fan and Heat Sinks
◦ Basically, computers come with two fans in the system unit or chassis, sometimes three. One CPU fan,
one case fan and sometimes, one hard drive fan. A manufacturer can also decide to put in more than
one CPU fan or case fan. During operations by the computer the CPU produces a lot of heat and heat
could always cause damage to your computer, that is why the CPU fan is put in place to keep the CPU
under the required temperature.

13. 6. CD-ROMs/DVD rom drives
◦ 6. CD-ROM/DVD-ROM drives
◦ Compact disc(CD) and digital versatile disc (DVDs) are storage devices onto which a certain amount of
audio files, data, and other computer files can be stored.

14. 7. PSU or Power Supply Unit
◦ 7. PSU or Power Supply Unit
◦ Just as any electronic device needs electrical power to function, so as the system unit’s components. But
the components do not work with the power from your wall socket so the computer power supply unit
receives the alternating current (AC) and converts it to a controlled direct current (DC) for the
components to function.

15. 8. Floppy disk drive
◦ 8. Floppy disk drive
◦ This is an internal hardware component in the system unit positioned closer to the CD-ROM drive and
its main function is to read and write from or on a floppy disk or diskette.

16. 9. SATA Serial Advance Technology
Attachment
◦ 9. SATA cable is mainly used to connect the internal hard drive to the computer motherboard. It can also
be used to connect a hard drive to a hard drive, and connect ATA and ATAPI devices to the computer
motherboard, and connect to an external computer.

17. 10. Video Card
◦ 10. A video Card is also called a video controller and appears as a circuit board to fit on motherboard.
The video card contains electronic circuits having GPU, visual processing units, heat sink, video BIOS,
video memory, RAMDAC, video graphics array, digital visual interface, HDMI, and display port.

18. 11. Computer Case
◦ 11. A computer case, also known as a computer chassis, tower, system unit, or cabinet, is the enclosure
that contains most of the components of a personal computer (usually excluding the display, keyboard,
and mouse). Cases are usually constructed from steel (often SECC—steel, electro-galvanized, cold-rolled,
coil), aluminum, and plastic.

19. Valuing
◦ 1. Why do we need to know the names and functions of the component of a system unit?
◦ 2. Cite the importance of knowing the names and functions of the component of the
system unit. Give examples.