Computer and its various parts :A PC consists of electronic components connected to various peripherals and accessories that let users send data to the computer (input) or receive information from the computer (output). Although PCs vary in shape, size, capacity, speed and price, they all include elements that enable them to perform the following essential tasks:
- Receive data
- Save data
- Manipulate data in various ways
- Generate result after processing data
Computers receive most data from either the keyboard or a hard disk. Information is usually saved on a hard disk. Data is manipulated and changed (processed) by the microprocessor, and the resulting output is either displayed on a monitor or printed on paper. However many computers may include additional components such as scanners, modems, magnetic tape drives, sound cards and so on.
The system unit, monitor, keyboard, mouse, etc. are the essential components of a computer and its functions are regulated by software and electronic parts. The internal parts of a computer are built with electronic circuits. The electronic components and internal connection within the system unit of a computer are discussed below:
- Monitor: Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. It displays both data entered by the user and information processed by the computer.
- Keyboard: It enables users to enter data or to type commands in order to perform specific operations. A keyboard contains keys for letters and numbers as well as for specialized tasks, such as Enter. Delete. Shift etc.
- Mouse: Mouse is a hardware input device that was invented by Douglas Engelbart in 1963. It lets users communicate with the computer by pointing at graphical objects on the screen, and then clicking a button to execute a command or display information.
- Printer: It lets users take a hard copy of information by transferring the results of their work onto paper.
- Motherboard: The main circuit board contained in any computer is called a motherboard. It is also known as the main board or logic board or system board or planar board. The biggest piece of silicon housed in the system unit of a computer is motherboard. All the other electronic devices and circuits of computer system are attached to this board like, CPU, ROM, RAM, expansion slots, PCI slots and USB ports. It also includes controllers for devices like the hard drive, DVD drive, keyboard and mouse. In other words, motherboard makes everything in a computer work together.
- Floppy Disk Drive: It reads and writes data on removable magnetic diskettes, thus enabling users to transfer information between computers, make copies of data for backup purposes, and install new programs.
- Power Supply: It transforms the 220-volt alternating current of electrical outlets into low- voltage direct current required by sensitive electronic components and peripherals.
- Expansion cards: Also called interface cards, they connect peripherals (such as monitors, disk drives, and so on) to the PC’s motherboard. They are essential for transferring and translating data to and from electronic devices.
- Hard Disk: It is the main storage area of a PC. It can hold huge amount of programs and information in magnetic form. It retains data even when the computer is switched off.
- CD/DVD Drives: A CD-ROM (Compact Disk Read Only Memory) drive uses disks to store large amounts of information. The disk for the CD-ROM drive is known as CD or CD-ROM disk. Data contained on these disks are audio files, software applications and graphics. Combo drives are also fitted that contain DVD and CD drive.
The Front Panel of a PC
The various panel components of a PC are described in the following sub-sections.
- Front panel
- Rear panel
Components of the Front Panel
The front of the PC contains the power switch, which is used to switch on the PC. There is the CD/DVD drive and the floppy drive. Various computer components of the front panel of a PC are discuss the below:
- Power Switch
- Reset Button
- Power Light (Power LED)
- Hard Disk Light (HDD LED)
- Sleep LED
- Floppy Drives
- CD-ROM/DVD Drive
Power Switch
Depending on the model, this switch is located either in the front or at the rear of the system unit. It is used to switch the system ON or OFF.
Reset Button
This is a press switch which can be used to restart the PC without switching off the mains power supply. However, use this switch as a last resort when the PC hangs and does not accept a command from the keyboard. When you restart the PC, it will lose all the information currently stored in its memory.
Power Light (Power LED)
It glows when the PC is ON and remains ON all the time. It is usually green in colour. LED is short for Light Emitting Diode.
Hard Disk Light (HDD LED)
It glows when the hard disk is being accessed and flashes when it reads or writes. It goes out when there is no disk activity. The hard disk light can be either green or red but usually it is red.
Sleep LED
Sleep LED light shows when the system is suspended, i.e., in ‘sleep’ mode.
Floppy Drives
Your PC may have one slot to fit floppy drive. PCs accept 3.5-inch floppy disk, which is used for storing data onto or for reading data from them.
CD-ROM/DVD Drive
It accepts CD-ROM disks and DVD disks.
Components of the Rear Panel
If you look at the rear panel of the system unit, you will see certain holes and slots fitted with different cables. On the back of the PC, you will see the power supply and the cooling fan. The Input/ Output ports of the PC are situated on the back of the PC. They are used to connect devices like the mouse and the keyboard. In addition, the back of the PC has several ports for connecting the sound devices, the monitor and the modem. Details of such ports are explained below:
- Video Port for Monitor
- Keyboard Port
- Mouse Port
- Power Sockets
- Parallel and Serial Port or Sockets
- Fan Housing
- USB Port
- Sound Connector
- Game Port and Joystick Connector
- Ethernet Port (RJ-45)
- Modem
Video Port for Monitor
The monitor is a very important computer peripheral that displays images and text generated by the computer video port which is a 5-pin socket for connecting a monitor with the system unit.
Keyboard Port
This is used to connect the keyboard with the system unit. It is usually a PS/2 port. Most modern keyboards can connect to the PC via a USB port instead of the standard PS/2 keyboard port. Because the USB uses a hub to enable multiple devices to connect to a single port. A single USB port in a system can replace the standard serial and parallel ports as well as the keyboard and mouse ports.
Mouse Port
It is a pointing device for moving and selecting items on the screen. It is the most commonly used pointing device. A mouse port is used to connect the mouse with the system unit. A mouse can be plugged into either the serial port or the PS/2 port.
Power Sockets
Cables plugged into these sockets carry electric power supply from the electrical outlet to your system unit and from there to the monitor.
Parallel and Serial Port or Sockets
The parallel port is a 25-pin female connector (DB-25). It is an interface for connecting external devices such a printers and computers that require relatively high bandwidth. Parallel ports are much faster than serial ports. These transmit data in a parallel manner. Parallel ports are wide in size to enable parallel transmission of data. A serial port is an interface for serial communication being transmitted at 1 bit at a time. This port can be used to connect a computer peripheral such as a modem, mouse, etc. These ports or sockets are used for expanding the capability of your PC. For example, you can connect a printer, mouse, modem or some other peripherals to your system unit.
Fan Housing
The power supply fitted inside the system unit has a small fan to release the heat out of the machine. You should make sure that the system unit is placed away from the wall so that the hot air released by the fan can be thrown out.
USB Port
Universal Serial Bus (USB) port is available in PCs. Many devices can be connected in series on the same USB. In comparison with serial and parallel ports, a large amount of data can be transferred at a very high speed through USB ports. All peripherals like the printer, modem and scanner are now available in versions that can be connected to the USB port. Two or more USB ports are normally seen in a PC’s system unit.
The USB is fast becoming a popular replacement for serial and parallel ports. This is because a USB is highly advanced, fast and simple to use.
Sound Connectors
Some PCs have in-built sound connectors but, in some systems they are on a separate expansion slots. There are three identical round rings i.e. output for speakers, input for microphone, and input for other devices.
Game Port and Joystick Connector
A joystick connector is a 15-pin female D-sub connector with two rows: One with 8 holes and the other with 7. The connector is also known as a game port and is used as a Music Instrument Digital Interface (MIDI) port for connecting computer peripherals such as a synthesizer and is located on the sound card.
Ethernet Port (RJ-45)
The ethernet port accepts an ethernet cable which allows you to communicate on a network that runs Transmission Control Protocol/Internet Protocol (TCP/IP). It is used to connect the network wire into the network computers
Modem
The word ‘Modem’ is a contraction of the words Modulator-Demodulator. It is typically used to send digital data over a phone line. A modem is required to surf the Internet or send or receive e-mail.
