what does a pc do?

Semester One 2001/2002

Sheffield Hallam University 1

What does a PC do?• computers collect, process, store,

and communicate information• Collect via input devices: mouse,

keyboard, scanner, digital camera• Process via CPU• Store onto storage devices: hard

disk, CD ROM, tape drive• Communicate via output devices:

monitor, printer, speakers, robot



Input Devices



Storage



Output Devices



Communications



Important Units

• Bit (Binary Digit, 0 or 1) is the smallest unit of info a computer can process

• Byte is eight bits - amount needed to represent one alpha-numeric character.

• Kilobyte (KB) is 1024 bytes, roughly half a page of text

• Megabyte (MB) is 1024 kilobytes• Gigabyte (GB) is 1024 megabytes



Power Supply• converts mains (AC) electricity to DC• PC uses 200 Watts, one unit of

electricity every five hours• Fan prevents parts from overheating

and keeps case size as small as possible

• Surge Protectors (optional) protect against voltage spikes

• Uninterruptable Power Supply (UPS, also optional) protects a computer from loss of power



Ports• Connectors at the back of the

computer where you plug in a peripheral device– modem, printer, mouse, keyboard

• Serial ports have 9 pins– Labelled COM1, COM2– Connect to mouse or modem

• Parallel ports have 25 connections– Labelled LPT1, LPT2– Connect to printers or tape drives



More Ports

• Keyboard ports• Games ports• USB - Universal Serial Bus

– allows several devices to be connected via only one port

– fast data transfer rate



Expansion Cards/Boards

• circuit boards that let you add a new feature to the computer

• PCs have a number of expansion slots– Buy a PC with plenty of slots spare

• Most cards go into the motherboard• Some plug into the back (Notebooks

and Laptops)



Types of Expansion Card• Video - generates images to

display on monitor• Modem - allows computers to

exchange information via telephone lines

• Sound - play and record audio• Network - to allow connected

computers to share information and peripherals

what does a pc do?

Documents