central_unit

Power Supply

• • A power supply is an electronic device that supplies electric energy to an electrical load.

The power supply unit converts alternating current (AC) from the main supply to the different direct current (DC) voltages required by the various components of the computer. It is responsible for all the power coming into the computer and maintains the right voltage. Most power supply units are built to conform to the ATX form factor. ATX power supplies are also designed to turn on or off based on a signal from the motherboard. It also provides support for modern functions like standby which are available in many computers.

Motherboard

• • A motherboard is the main printed circuit board (PCB) found in computers and other expandable systems. It holds many of the crucial electronic components of the system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals.

Microprocessor

• • The microprocessor is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic, as it has internal memory. Microprocessors operate on numbers and symbols represented in the binary numeral system.

• Multicore processors (2, 4, 6, 8) have more than one processor “core” on a single silicon chip which allows computers to run faster.

• A graphics processing unit (GPU) is a specialized processor used to manipulate three-dimensional(3- D) computer graphics.

The motherboard is also known as the system board or main board and is the main circuit board of the microcomputer. It is a big connecting platform fixed to the bottom of the system unit and has a variety of chips and other smaller boards attached to it. The motherboard is sometimes referred to as the spine of the computer because all devices used on the computer need to be connected in one way or another to the motherboard.

Typically, external devices like the monitor and printer connect to the motherboard by plugging into their respective ports which are exposed through the exterior of the system unit case. Some of the major components attached to the motherboard are the CPU, storage drives, memory and expansion slots.

Processing Speed

• Every microprocessor contains a system clock, which controls how fast all the operations within a computer take place (the chip’s processing speed).

• Older CPU processing speeds are in megahertz.

  • 1 MHz = 1 million cycles per second

• Current CPU processing speeds are in gigahertz.

  • 1 GHz = 1 billion cycles per second

• The faster a CPU runs, the more power it consumes, and the more heat it generates

The Central Processing Unit (CPU)

The CPU also known as the processor or the microprocessor is the main processing device in the computer system that carries out the instructions of a computer program. It is responsible for performing the basic arithmetic, logical, and input/output operations of the computer. Most PCs today use CPUs manufactured by Intel or Advanced Micro Devices (AMD).

The CPU is usually attached with a heat sink and a cooling fan. The heat sink absorbs heat from the CPU and the fan blows the heat away.

Memory

The term memory is usually used to refer to the computer’s main memory called Random Access Memory (RAM). RAM is considered to be the working area of the computer because when the computer is in operation that is where instructions and data being worked on by the CPU are stored. RAM is volatile because it holds data only when the power is on and loses its content when the computer is switched off.

Expansion Slots and Cards

The motherboards of most desktop computers have a variety of expansion slots into which expansion cards are inserted when the need arrives to add additional peripherals and functionality to the computer. Expansion cards are also called add-in boards, adapter cards, adapter boards, etc. and they can be in the form of network cards, sound cards, VGA graphics cards, TV/Radio cards, etc.

Hard Disk Drive

A hard disk drive is a high capacity, non-volatile, magnetic data storage device that is usually non-removable. It features one or more rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is encoded magnetically by read/write heads that float on a cushion of air above the platters.

Port

There are many type of port that are available such as :

• Serial port : Used to transmit data slowly over long distance

  • Sends data sequentially, one bit at a time

  • Used to connect older keyboards, mouse, monitors, dial-up modems

• Parallel port : For transmitting data quickly over short distances

  • Transmits 8 bytes simultaneously

  • Connects printers, external disks, tape backups

• USB port : Universal Serial Bus high-speed hardware standard for interfacing peripheral devices, such as scanners and printers, to computers without a need for special expansion cards or other hardware modifications to the computer. USB is replacing many varieties of serial and parallel ports.

• FireWire : Intended for multiple devices working with lots of data and requiring fast transmission speeds, such as DVD drives, digital video cameras, and gaming consoles.

• Ethernet : Supports a network standard for linking a wired local area network and connecting it to a DSL or a cable modem for high-speed Internet access.

• Graphics : Connects digital monitors and multimedia digital devices, such as TVs and DVD players.

• eSATA : External Serial Advanced Technology Attachment; allows the attachment of an eSATA hard disk, which has fast data transmission speeds.

• Bluetooth : Connects devices that use short-range radio waves that transmit up to 30 feet.

• IrDA :Transfers data via infrared light waves between directly aligned devices, as between a smartphone and a desktop computer.

• HDMI : High-Definition Multimedia Interface; carries both video and audio signals and is used for connecting HDTVs, DVD players, and game consoles to computers, laptops, and other devices.

• MIDI : Musical Instrument Digital Interface; used to connect electronic musical instruments to a sound card that converts the signals to digital instructions that can be saved or manipulated.