Computer Tutorial

Sound cards:-

                                      allow computers to produce sound like music and voice. The older sound cards were 8 bit then 16 bit then 32 bit. Though the human ear can't distinguish the fine difference between sounds produced by the more powerful sound card they allow for more complex music and music production

Modem:-

                    A modem is used to translate information transferred through telephone lines, cable or line-of-site wireless. The term stands for modulate and demodulate which changes the signal from digital, which computers use, to analog, which telephones use and then back again. Digital modems transfer digital information directly without changing to analog.
Modems are measured by the speed that the information is transferred. The measuring tool is called the baud rate. Originally modems worked at speeds below 2400 baud but today analog speeds of 56,000 are standard. Cable, wireless or digital subscriber lines can transfer information much faster with rates of 300,000 baud and up.
Modems also use Error Correction which corrects for transmission errors by constantly checking whether the information was received properly or not and compression which allows for faster data transfer rates. Information is transferred in packets. Each packet is checked for errors and is re-sent if there is an error.
Anyone who has used the Internet has noticed that at times the information travels at different speeds. Depending on the amount of information that is being transferred, the information will arrive at it's destination at different times. The amount of information that can travel through a line is limited. This limit is called bandwidth.
There are many more variables involved in communication technology using computers, much of which is covered in the section on the Internet.

Printers:-

                   The printer takes the information on your screen and transfers it to paper or a hard copy. There are many different types of printers with various levels of quality. The three basic types of printer are; dot matrix, inkjet, and laser.

• Dot matrix printers work like a typewriter transferring ink from a ribbon to paper with a series or 'matrix' of tiny pins.
• Ink jet printers work like dot matrix printers but fires a stream of ink from a cartridge directly onto the paper.
• Laser printers use the same technology as a photocopier using heat to transfer toner onto paper.

Digital flash drives:-

work slightly differently as they use memory cards to store information so there are no moving parts. Digital cameras also use Flash memory cards to store information, in this case photographs. Hand held devices use digital drives and many also use memory cards.