A computer is an electronic machine that performs
calculations based on a set of instructions.
A computer system consists of hardware and software
components.
Hardware is the physical equipment. It includes the
case, storage drives, keyboards, monitors, cables,
speakers, and printers.
Software includes the operating system and programs.
Cases
The computer case contains the framework to support the internal components while providing an
enclosure for added protection. Computer cases are typically made of plastic, steel, or aluminum and
are available in a variety of styles.
Cases also provide an environment designed to keep the internal components cool.
Several factors must be considered when choosing a case: Size of the motherboard, Number of
external or internal drive locations and Available space
Power Supplies
The power supply must provide enough power for the components that are currently installed and
allow for other components that may be added at a later time.
If you choose a power supply that powers only the current components, you might need to replace the
power supply when other components are upgraded.
Internal PC Components
Motherboards
The motherboard is the main printed circuit board
and contains the buses, or electrical pathways, found
in a computer.
The form factor of
motherboards
pertains to the size
and shape of the
board. It also
describes the physical
layout of the different
components and
devices on the
motherboard.
CPUs
The central
processing
unit (CPU) is
considered
the brain of
the computer.
Most calculations take place in the CPU, the
most important element of a computer system.
The CPU
socket or slot
is the
connection
between the
motherboard
and the
processor.
Cooling Systems
The flow of current
between the electronic
components generates
heat.
Computer components perform better when kept cool.
Increasing the air flow in the computer case allows more heat to be removed.
ROM
Read-only memory
(ROM) chips are located
on the motherboard and
other circuit boards.
Contain instructions that can be directly accessed by
a CPU such as booting the computer and loading the
operating system.
RAM
RAM is the temporary storage for data and programs that are being
accessed by the CPU.
Volatile memory,the contents are erased when
the computer is powered off.
More RAM = More capacity to hold and process large programs and files.
Enhances system performance.
External Ports
Video Ports
Connects a monitor to a computer using a cable.
Transfer analog signals, digital signals, or both.
An input device enters data or instructions into a computer.
E.g: Mouse, Keyboard ,Gamepad, Digital camera....
Output Devices
An output device presents information to the user from a computer.
E.g: Monitors and projectors, Printers, Fax machines, Headphones...
Electricity & Ohm's Law
These are the four basic units
of electricity: Voltage (V),
Current (I), Power (P),
Resistance (R).
Voltage is a measure of work required to move a
charge from one location to another. Voltage is
measured in volts (V). A computer power supply
usually produces several different voltages.
Current is a measure of the amount of
electrons moving through a circuit per second.
Current is measured in amperes, or amps (A).
Power is a measure of the work required to move electrons through a
circuit (voltage), multiplied by the number of electrons going through that
circuit per second (current). The measurement is called watts (W).
Computer power supplies are rated in watts.
Resistance is the opposition to the flow
of current in a circuit, measured in ohms.
Lower resistance allows more current to
flow through a circuit.