Fundamental of output device

Output device

The device through which computer display the processed result at the end of each process is known as Output Device.
Example -Monitor, Printer, Speaker, Headphone, Plotter etc.

The monitor is an important output device. It is also known as Visual Display Unit(VDU). It is used to display the processed result in a screen form of a soft copy. Without a monitor, the system can't work.


There are three types of monitor

CRT(Cathode Ray Tube)
CRT stands for cathode ray tube. These are all old model monitors. Main disadvantages are heavyweight, occupy more place, high power consumption, high radiation and support the low resolution. These are all main reasons to prefer LCD or LED monitors.

LCD(Liquid Crystal Display)  
LCD stands for liquid crystal display. The main advantage of LCDs are light weighty, occupy less place, 12 volts power consumption, low radiation and supports high resolutions.

LED(Light Emitting Diode)  
LED stands for the light emitting diode. Actually, there are no differences between LCD and LED monitors, but better picture quality in LED monitors. So now all are prefer LED monitors than LCD monitors.

This is used to print the hard copy of any processed result on a page.


Types of printer

Dot-matrix printer  
These printers have print head comprising of a matrix tiny needles, typically 7 rows with 9 needles each(9*7 matrix), which hammers out characters in the form of patterns of tiny dots. The shape of each character is stored electronically in the printer. Dot-matrix printers are less expensive, faster and can print any shape of character and graphics.
INK: Ribbon.

Ink-jet printer  
Ink-jet printers function like dot-matrix printers. They form images or characters with small dots. In these printers, dots are formed by tiny droplets of ink. The speed of these printers is up to about 270 c.p.s. they produce less noise. There are several manufacturers producing color ink-jet printers. In some of these printers, all color inks are in one cartridge. For replacing one color you have to replace all the colors but in some other color ink-jet printers, you can replace inks individually. For those who use one color predominantly, these printers are better.
INK: Cartridges.

Laser printer  
In this technology, no print head move and no print hammers hit. Therefore the speed is very high and the noise is negligible. It functions like a photostat machine. A laser beam is directed across the surface of a light-sensitive drum and fired as needed an image is thus recorded in the form of a pattern of tiny drops. The image is then transferred to the paper, using a special toner. Laser printers have a very high speed and level of noise is very low. The quality of the printers is very high and these printers are also useful for excellent graphics work. Their maintenance requirement is also very low.
INK: Toner Cartridges.



Speakers are another type of output device, which allows you to listen to a voice like music and conversation with people.


Headphones are an output device. They are similar to speakers, except they are worm on the ears so only one person can hear the output at a time.


Plotters are specialized output devices which produce high-quality graphics in various colors. Some of the plotters use pens which others do not. Drum plotters and flatbed plotters both use pens. Electrostatic plotters do not in a drum plotter, the paper is mounted on the surface of a drum. As drum revolves, the plotter pens are horizontally positioned over the printing areas as the paper rotates to the correct point. The pens are dropped to the surface and moved left and right across the paper as the drum revolves. After the image is completed, the pens are raised from the surface. In flatbed plotters, the paper is placed flat and one or more pens move horizontally and vertically across the paper. Electrostatic plotters use electrostatic charges to create images with small dots on specially treated paper. The paper is run by a developer to allow the image to appear. Electrostatic plotters are faster and produce very high-resolution images. Many 2 to 8 pens flatbed plotters are available for microcomputer systems. Like some small drum plotters, large plotters can produce drawings up to 8*8 feet or even larger. These plotters are used with large computer systems.

No comments :