Output Device (Soft copy output)

Output Device

Output is anything that comes out of a computer. Output can be meaningful information, and it can appear in a variety of forms – as binary numbers, characters, pictures, sounds and printed pages. The computer communicates with the user via the output devices. The function of output device is to present processed data to the user. It receives information from CPU and present into the user in the desired form. The output can normally be produced in two ways; either on a display unit i.e. screen or in paper. Output on a computer screen which is in electronic form is softcopy output whereas output on a paper which is in non-electronic form is hardcopy

Generally output is of two types:

• Soft copy output
• Hardcopy output

Softcopy Output:

A softcopy output is the unprinted digital document file.It is viewed in the screen via different programs like word processing, excel, and other.  The soft copy output devices are: Monitor, Speaker, Headphone, Multimedia projector, etc.Some of the commonly used softcopy output devices are:

Monitor: Monitor is another term for the display screen. The term monitor usually refers to the entire box, where as display screen can mean just the screen. A monitor is commonly used as softcopy output devices. There are two types of monitors that are used with personal computers

• CRT monitors
• Flat-panel monitors

CRT Monitors

The Cathode Ray Tube (CRT) consists of a vacuum tube containing an electron gun and fluorescent screen. There are different internal and external means which are used to accelerate and deflect the electron beam on the fluorescent screen, used to form an image in the form of light emitted from the fluorescent screen. A CRT is a partially evacuated glass tube which is filled with an inert gas at very low pressure. It works by moving an electron beam back and forth across the back of the screen. Each time the beam makes a pass across the screen, it lights up phosphor dots on the inside of the glass tube, there by illuminating the active portions of the screen. By drawing many such lines from the top to the bottom of the screen, it creates an entire screen of images. Near the back of the CRT monitor there is an electron gun. The gun sends out a beam of electrons through a magnetic coil, which aims at the front of the monitor. The back of the monitor screen is coated with phosphors- chemical that glow when they are struck by electron beam. The screen’s phosphor coating is arranged as grids of dots called picture elements or pixel.

CRT monitors have long been used with desktop computers and are still being used for most applications. They are cheap and heavy, take up a lot of desktop space and are difficult to move as they are very heavy. It requires a lot of power because of this disadvantage now many people are turning to flat-panel monitors.

Flat Panel Monitor:

Flat Panel Monitors have long been used with portable computers. But in the last few years the flat panel monitors are being increasingly used with desktop computers. There are several types of flat panel monitors. The most common is the Liquid Crystal Display (LCD) monitor. The LCD technology is the same that is used in calculators and digital screen. It creates images with a special liquid crystal that is transparent but becomes opaque when charged with electricity. Liquid crystals do not emit light directly. Calculators and digital watches also have the technology of LCD. The LCD monitor creates images with a special liquid crystal that is normally transparent but becomes opaque when charged with electricity. LCD is an electro-optical amplitude modulator realized as a thin, flat display device made up a number of color or monochrome pixels arrayed in front of a light source or reflector.

LED is new technology in flat panel monitor. Light Emitting Diode (LED) is an emissive display device in which matrix of diodes is arranged to form the pixel positions in the display. Emitting diodes plays an indispensable role today in many electrical and electronic devices. It has features of low power requirement, less heat production, high efficiency and better quality image.

Speaker:

Speakers are output device which produce output as a audio sound and its volume can be adjusted as per requirement. It is used to address a mass of people or to hear around in the room. Sound card is necessary for the production of sound through speaker. The sound card translates digital sound into electrical current that is sent to the speakers which we hear. It can be used while talking with other people using internet or some other technology. Normally speakers has left and right speakers, they can be adjusted as to listen sound from only one left or right speaker or from both. It consumes electricity for the output of sound. Headphones also fall under this category which has the same principle as speaker but in small sound. It allows us to listen to music or sound privately without disturbing anyone around us.

Multimedia Projector:

Multimedia projectors are self-content data projection units. While most are primarily used for computer based presentation, many can also handle additional data sources such as VCR and DVD players. All multimedia projectors have a light source, a lens, and at least one RGB input (computer). Multimedia means that a projector will display data from computers as well as pictures from the televisions and video recorders. Video-only projectors cannot be used with computers. In the world of multimedia projectors, not all pictures are created equal. These projectors use many rows of small elements called pixels to make the image we see. The amount of detail your projector can display, and the clarity with which it will be seen, depends on how many pixels are projected. It is called projector resolution and it is usually in two sets of number i.e. 1200x800. The first number refers to the pixels displayed horizontally across the image; the second to those displayed vertically from top to bottom. The more pixels there are, the higher the projector’s resolution, and the more detail that can be seen in the projected images. Projected images are sharpest when computer and projector resolution match. It is a good idea to keep your computer in mind as you shop for a projector. The usual resolutions are 800 x 600 (SVGA), 1024 x 768 (XGA) and 1280 x 1024 (SXGA).

The multimedia projector will have data input and output ports. The more expensive a multimedia projector is, the more inputs/outputs ports it is likely to have. Some projector has feature of “RGB In” port which allows us to connect more than one computer at a time to the projector. The “RGB Out” port allows us to connect a separate external monitor to our projector. There is also feature of audio in and audio output. The audio in port is connected to computer, DVD, VCR for the sound. In the large, we have to connect with external speaker for the extra sound.