Plotter

Plotter is a device that draws pictures on paper based on commands from a computer. Plotter differ from printer in that they draw lines using a pen. As a result, they can produce continuous lines, whereas printers can only simulate lines by printing a closely spaced series of dots. Multicolour plotter use different coloured pen to draw different colour.

In, general, plotters are considerably more expensive than printer. They are used in engineering applications where precision is mandatory

Sound cards and speakers

An expansion board that enables a computer to manipulate and output sounds. Sound cards are necessary for nearly all CD-ROMs and have become commonplace on modern personal computers. Sound card enable the computer output. Sound through speakers connected to the board.