A peripheral is any computer device that is not part of the essential computer but is relatively close by. Peripherals are often called input/ output (I/O) devices. Some peripherals are in the same case as the main part of the computer, such as the hard drive or CD-ROM drive. Other peripherals, such as the printer, monitor, or scanner, are outside the computer case and are attached by a wired or wireless connection.
Input devices
1. Keyboard: A keyboard is the main input device for text and commands. The computer keyboard uses the same key arrangement as typewriters but also contains standard function keys, such as the escape, cursor movement, and control keys. If you’re planning to type at a computer for long periods of time, you might consider purchasing an ergonomic keyboard.
2. Mouse: A mouse is an input device that sits on the work surface beside the computer. The computer user pushes the mouse across the work surface to point to a place on a display screen and to select one or more actions to take from that position.
3. Trackball/Touchpad: These devices are used in many notebook and laptop computers. The user may roll the ball to direct the cursor to the desired place on the screen and click a button (like a mouse button) near the trackball to select objects or position the cursor for text entry. A touchpad is a pressure-sensitive screen that users navigate with their fingertips. Trackballs or touch-pads also may be used to help with ergonomic concerns.
4. Modem: A modem provides a communication link between your computer and a telephone line. The modem may be inside the computer or outside connected by a cable. Some modems offer features such as fax, speakerphone, caller ID, and voice mail.
5. Joystick: A joystick is used mostly for computer games. Usually placed in front of the computer, a joystick has a square base with a lever attached to the top of it. When moving the joystick forward the graphic object on the computer moves up, and moving the lever back moves the object down.
6. Digitizing tablet: A device that enables the user to enter drawings and sketches into a computer. It consists of an electronic tablet and a cursor or pen. The tablet detects movements of the cursor or pen and translates the movements into digital signals. The pen (also called a stylus) looks like a simple ballpoint pen but uses an electronic head instead of ink.
7. Scanner: A scanner captures images (black and white or color) from photos, posters, or magazine pages for computer editing and display. Scanners usually come with software that allows you to resize and modify a captured image. Scanners also can be used to convert text on printed pages into editable computer files. There are three main types of scanners for the consumer market. Sheet-fed scanners resemble a small fax machine with a paper tray for inputting sheets. Flatbed scanners look like the top half of a copy machine. Though they take up more space, you can scan books or magazines that are too thick to fit through a sheet-fed scanner. Slide scanners are designed to scan 35-mm slides and negatives. They have a very compact scanning unit that can get detailed information from small images.
8. Touch screen: A touch interface allows users to navigate a computer system by touching icons or links on the screen. A person without any computer experience may easily use a touch screen system. Touch interface technology is advanced enough for most PC systems (including Windows and Macintosh platforms) so that the hardware simply may be plugged in without any difficult programming. It is easy to add the interface to existing applications or develop new applications.
9. Digital camera: A digital camera records and stores photographic images in digital form. The images can be fed to a computer as they are recorded or stored in the camera for later loading into a computer.
Storage devices
1. Hard drive: A hard drive is a storage device inside the computer where information is stored permanently. Currently hard drives range from 4 GB to 36 GB or more. One gigabyte stores the equivalent of about 711 floppy (1.44 MB) diskettes.
2. CD-ROM drive: CD-ROM technology is a format and system for recording, storing, and retrieving electronic information. A CD-ROM disk is the same size as a music CD and holds more than 650 MB of text, graphics, video, and sound. CD-R and CD-RW drives Ñ CD-Recordable (CD-R) and CDR-Writeable (CD-RW) drives allow users to store 650 MB of information. Transferring information of this kind is also called “burning” a CD. CD-Recorders permanently write data to special CD-R media. Once a CD-R disc is altered by a laser, it’s changed forever. CDR-Writeable drives take the technology used by CD-R one step further by allowing users to rewrite over old data several times.
3. DVD drive: DVD (digital versatile disk) is an optical disk technology that is expected to replace the CD-ROM disk during the next few years. A DVD holds 4.7 GB of information per layer. With two layers on each of its two sides, a disk holds up to 17 GB of video, audio, or other information-enough for a 133-minute movie. DVD-ROM is the name of the player for DVDs and CD-ROM disks. DVD-RAM is the writeable version. DVD-Audio is a player designed to replace your compact disc player.
4. Tape, tape drive, and tape cartridge: Tape is an electromagnetic storage medium that typically is both readable and writeable. A tape drive is the device that positions, reads from, and writes to the tape. A tape cartridge is a protectively-encased tape that is portable. In early business computers, tape was a primary storage medium, but with the development of the magnetic disk, tape has been used mostly for backing up large amounts of data on servers and mainframes. Today, it is still used for archiving purposes, and new forms are being used for automatic backup.
Output Devices:
1. Monitor: A monitor (also called display, CRT, or screen) is a computer display that is separate from other parts of the computer. Like a TV monitor, a computer monitor image is made up of pixels (dots). In general, the higher the resolution the better the image. The smaller the dots pitch (typically from 0.25 mm to 0.31 mm), the crisper the image. Faster refresh rates are easier on the eyes and allow you to sit in front of the computer for longer periods of time.
2. Dot matrix printer: The dot matrix printer is an impact printer. It works like an automatic typewriter. It is a low-cost printer with low quality output. Because it is an impact printer, it may be used when carbon copies of a document are required.
3. Ink jet printer: The ink jet printer is a non-impact printer. The ink jet sprays ink from an ink cartridge at very close range to the paper as it rolls by. This is a low-cost printer with a mid-quality output. This type of printer is the most economical for color output.
4. Laser printer: The laser printer uses a laser beam reflected from a mirror to attract ink (called toner) to selected paper areas as a sheet rolls over a drum. A laser printer is the most expensive type of printer with the best output.
5. Fax or fax modem: Sometimes called “tele-copying”, a fax is the telephonic transmission of scanned-in printed material (text or images), usually to a telephone number associated with a printer or other output device. The original document is scanned with a fax machine, which treats the contents (text or images) as a single fixed graphic image. In this digital form, the information is transmitted as electrical signals through the telephone system. The receiving fax machine reconverts the coded image and prints a paper copy of the document.
Input devices
1. Keyboard: A keyboard is the main input device for text and commands. The computer keyboard uses the same key arrangement as typewriters but also contains standard function keys, such as the escape, cursor movement, and control keys. If you’re planning to type at a computer for long periods of time, you might consider purchasing an ergonomic keyboard.
2. Mouse: A mouse is an input device that sits on the work surface beside the computer. The computer user pushes the mouse across the work surface to point to a place on a display screen and to select one or more actions to take from that position.
3. Trackball/Touchpad: These devices are used in many notebook and laptop computers. The user may roll the ball to direct the cursor to the desired place on the screen and click a button (like a mouse button) near the trackball to select objects or position the cursor for text entry. A touchpad is a pressure-sensitive screen that users navigate with their fingertips. Trackballs or touch-pads also may be used to help with ergonomic concerns.
4. Modem: A modem provides a communication link between your computer and a telephone line. The modem may be inside the computer or outside connected by a cable. Some modems offer features such as fax, speakerphone, caller ID, and voice mail.
5. Joystick: A joystick is used mostly for computer games. Usually placed in front of the computer, a joystick has a square base with a lever attached to the top of it. When moving the joystick forward the graphic object on the computer moves up, and moving the lever back moves the object down.
6. Digitizing tablet: A device that enables the user to enter drawings and sketches into a computer. It consists of an electronic tablet and a cursor or pen. The tablet detects movements of the cursor or pen and translates the movements into digital signals. The pen (also called a stylus) looks like a simple ballpoint pen but uses an electronic head instead of ink.
7. Scanner: A scanner captures images (black and white or color) from photos, posters, or magazine pages for computer editing and display. Scanners usually come with software that allows you to resize and modify a captured image. Scanners also can be used to convert text on printed pages into editable computer files. There are three main types of scanners for the consumer market. Sheet-fed scanners resemble a small fax machine with a paper tray for inputting sheets. Flatbed scanners look like the top half of a copy machine. Though they take up more space, you can scan books or magazines that are too thick to fit through a sheet-fed scanner. Slide scanners are designed to scan 35-mm slides and negatives. They have a very compact scanning unit that can get detailed information from small images.
8. Touch screen: A touch interface allows users to navigate a computer system by touching icons or links on the screen. A person without any computer experience may easily use a touch screen system. Touch interface technology is advanced enough for most PC systems (including Windows and Macintosh platforms) so that the hardware simply may be plugged in without any difficult programming. It is easy to add the interface to existing applications or develop new applications.
9. Digital camera: A digital camera records and stores photographic images in digital form. The images can be fed to a computer as they are recorded or stored in the camera for later loading into a computer.
Storage devices
1. Hard drive: A hard drive is a storage device inside the computer where information is stored permanently. Currently hard drives range from 4 GB to 36 GB or more. One gigabyte stores the equivalent of about 711 floppy (1.44 MB) diskettes.
2. CD-ROM drive: CD-ROM technology is a format and system for recording, storing, and retrieving electronic information. A CD-ROM disk is the same size as a music CD and holds more than 650 MB of text, graphics, video, and sound. CD-R and CD-RW drives Ñ CD-Recordable (CD-R) and CDR-Writeable (CD-RW) drives allow users to store 650 MB of information. Transferring information of this kind is also called “burning” a CD. CD-Recorders permanently write data to special CD-R media. Once a CD-R disc is altered by a laser, it’s changed forever. CDR-Writeable drives take the technology used by CD-R one step further by allowing users to rewrite over old data several times.
3. DVD drive: DVD (digital versatile disk) is an optical disk technology that is expected to replace the CD-ROM disk during the next few years. A DVD holds 4.7 GB of information per layer. With two layers on each of its two sides, a disk holds up to 17 GB of video, audio, or other information-enough for a 133-minute movie. DVD-ROM is the name of the player for DVDs and CD-ROM disks. DVD-RAM is the writeable version. DVD-Audio is a player designed to replace your compact disc player.
4. Tape, tape drive, and tape cartridge: Tape is an electromagnetic storage medium that typically is both readable and writeable. A tape drive is the device that positions, reads from, and writes to the tape. A tape cartridge is a protectively-encased tape that is portable. In early business computers, tape was a primary storage medium, but with the development of the magnetic disk, tape has been used mostly for backing up large amounts of data on servers and mainframes. Today, it is still used for archiving purposes, and new forms are being used for automatic backup.
Output Devices:
1. Monitor: A monitor (also called display, CRT, or screen) is a computer display that is separate from other parts of the computer. Like a TV monitor, a computer monitor image is made up of pixels (dots). In general, the higher the resolution the better the image. The smaller the dots pitch (typically from 0.25 mm to 0.31 mm), the crisper the image. Faster refresh rates are easier on the eyes and allow you to sit in front of the computer for longer periods of time.
2. Dot matrix printer: The dot matrix printer is an impact printer. It works like an automatic typewriter. It is a low-cost printer with low quality output. Because it is an impact printer, it may be used when carbon copies of a document are required.
3. Ink jet printer: The ink jet printer is a non-impact printer. The ink jet sprays ink from an ink cartridge at very close range to the paper as it rolls by. This is a low-cost printer with a mid-quality output. This type of printer is the most economical for color output.
4. Laser printer: The laser printer uses a laser beam reflected from a mirror to attract ink (called toner) to selected paper areas as a sheet rolls over a drum. A laser printer is the most expensive type of printer with the best output.
5. Fax or fax modem: Sometimes called “tele-copying”, a fax is the telephonic transmission of scanned-in printed material (text or images), usually to a telephone number associated with a printer or other output device. The original document is scanned with a fax machine, which treats the contents (text or images) as a single fixed graphic image. In this digital form, the information is transmitted as electrical signals through the telephone system. The receiving fax machine reconverts the coded image and prints a paper copy of the document.
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