Plotters and speaker

Plotters are hardcopy output devices used for large linear drawings. The drawing or design is conveyed to the paper surface by plotting a serial of points and connecting them with lines. Plotters are most often used for drafting or map making. Early plotters were bulky, mechanical devices that used robotic arms, which literally drew the image on a piece of papers. Table Plotters (Flatbed Plotter) use two robotic arms, each of which holds a set of colored ink pens or pencils. The two arms work in a concert, operating at the right angles as they draw on a stationary piece of paper. In addition to being complex and large, table plotters are slow.

A variation on the table plotter is the Roller Plotter which uses only one drawing arm but move the paper instead of holding it flat and stationary. The drawing arm moves side to side as the paper is rolled back and forth through the roller. Working together, the arm and roller can draw perfect circles and other geometric shapes, as well as lines of different weight and colors.
In recent years, mechanical plotters have been displaced by thermal, electrostatic and ink jet plotters. These plotters are faster and cheaper to use than their mechanical counter parts. It can produce full color renderings as well as geometric line drawings, making them useful than standard mechanical plotters.

Speaker

A speaker is a softcopy output device that plays sound generated by the computer. They are usually in a group of two and come in various sizes and shapes. You can listen to songs which are stored on the hard disk of the computer through the speaker. Speakers are used with a computer system to produce output in the form of sound. Some computer games and educational CD’s can be played and understood only when the sound is heard. For that purpose, speakers must be attached with the computer. Speakers are helpful for blind people, who can hear the sound but can not see the information (output) on the monitor.