More Related Content
What's hot
What's hot (18)
Recently uploaded
Recently uploaded (20)
Peripherals and Backing Storage
- 2. INPUT DEVICES Camera Scanner Keyboard Mouse
- 3. OUTPUT DEVICES Monitor Printer Plotter
- 4. CABLING Coaxial Optical Twisted pair
- 6. TYPES Disks Flash memory cards Optical media USB drives
Editor's Notes
- One type of input device is a camera. This could either be a digital camera connected through a USB port or a webcam. These input images into the computer. Another input device is a scanner. This senses reflections on paper by shining a light over it. It then interprets the reflections as text/images. A keyboard inputs data into a computer with keys. The main format of a keyboard is QWERTY, but there are other formats such as AZERTY and dvorak.A mouse moves a pointer around the screen and has buttons that you can press to perform different functions.
- One type of output device is a monitor. There are two main types of monitor, one of them is a Cathode Ray Tube. This is an old type of monitor and they aren’t in production anymore. An electron gun is inside that projects electron beams onto the screen to form images. These monitors produced a lot of heat and took up a lot of space.An LCD monitor is another type. This stands for Liquid Crystal Display. These are a lot more efficient than CRT monitors, they need less power to run and they produce a lot less heat. These work by having two sheets of material either side of a liquid crystal, which passes an electric current through which makes the crystals align to block the light or let it pass through.There are 3 main types of printer. One is an inkjet. This sprays ink onto the paper. This is quite an expensive form of printing, it is found in homes. The ink often smudges as well.Another type is a laser. This is a lot faster than laser printing. It lasers the image onto a drum, which then picks up toner (particles of plastic) and puts it onto the paper. It then heats the paper so the toner melts onto the paper.The third type is a dot matrix. This is also known as an impact printer. This is a low resolution method of printing. There is a row of 8, 9 or 24 pins that stamp letters onto paper, similar to a typewriter.A plotter is a printer used in CAD (computer aided design). It is used to print vector graphics and blue prints for buildings.
- Coaxial cabling is generally used for connecting networks. It has an inner wire that is surrounded by plastic, more wire, and then the plastic outer casing. It is also used to transmit low frequency radio/audio transmission.Optical cabling is the fastest type of cabling, because it uses optical fibres to send light as information. The fibres are coated with polyimide to stop them from getting damaged. Modern optical cabling can have speeds of up to terabytes per second.Twisted pair cabling is two insulated wires twisted together to reduce electronic interference. This type of wire was mainly used for old telephone wires, and is also used in networks as Ethernet cables. Twisted pair is quite slow, but it is the cheapest type of wiring.
- Hard disks are one type of backing storage. They are fixed drives, but they can also be connected externally through a USB connection linked to the motherboard. The are one or multiple magnetic disks rotating at a high speed with a magnetic head moving over them reading and writing the data. Hard disk drives aren’t that close to the motherboard, which means that data isn’t accessed that quickly. That’s why there is RAM and caches so that data can be temporarily stored there. Hard drives capacity high, up to around 3-4TB of data.Flash memory cards such as SD cards are used in cameras and phones. They are small and re-recordable. They also retain the information stored on them when they aren’t connected to power. They can hold up to 265GB of data at the moment. When the chips in flash memory become worn out, the transfer rate slows down considerably. The quality of the flash memory also effects the transfer rate.Optical media includes things such as CDs or DVDs. They are read by a laser moving across the surface at a high speed reading a flat or a raised surface, which represents a 1 or a 0. You can get 3 types of CD/DVD, they are CDROM (read only) CDRW (rewrite) and CDR(rewrite once). DVDs can hold a lot more data than CDs. DVDs can hold up to 4.37GB of data, whereas CDs can only hold up to 737MB. Optical disks transfer rates are relatively fast, but not as fast as flash memory as the disk has to be spun for the information to be read. Any scratches on the surface of a disk can alter the information.USB drives are a type of flash memory, and are used to transfer data between computers. The maximum capacity of a USB drive currently is 1TB. The transfer rates of these are very fast, however the speed lessens the more worn the drive is, similar to other flash memory.