Chapter 14 - Computers and Peripherals

Abstract

A computer is a programmable microprocessor system with a large amount of random access memory (RAM), a keyboard, and a visual display unit (VDU) as minimum requirements. A peripheral is a device that is connected to a computer to perform such actions as display, printing, selection of operations, and communication. Calculators and computers use a microprocessor as the main programmable unit. Calculators generally use only a number keyboard and a number display, with a small memory. Computers use a much wider range of connections such as hard and floppy drives, compact disc (CD) units, soundboards, scanners, light pens, full-sized keyboards, and cathode-ray tube (CRT) monitors. The word modem is derived from the words modulation and demodulation, and is used to connect computers over telephone lines. Modern monitors, mostly LCD types are capable of high resolution and a full range of color, 24 million colors or more. A graphics card is the interface between the computer and the monitor. It contains a processor of its own (a graphics processor), with support chips and memory. A sound card (or sound board) is used as a way of allowing the computer to work with digital sound signals, such as the output from a music CD. The sound card is added to the PC, or it can be incorporated on the main board (motherboard). Printers for small computers are either inkjet or laser types. A scanner is a valuable peripheral that allows one to digitize documents that consist of text and/or images.