Peripherals (2)

 

Keyboard

 

A long key at the bottom of the keyboard. Each time it is pressed, it produces a blank space.
 
It leafs through your text one page down.
 
It moves the cursor to the beginning of a new line. It is also used to confirm commands.
 
It stops a program without losing the information from the main memory.
 
It works in combination with other keys to produce special characters or specific actions.
 
It removes the character on the left of the cursor or any selected text.
 
It produces capital letters as long as you press it.
 
It produces capital letters as long as it is locked.
 
It moves the cursor horizontally to the right for a fixed number of spaces.
 
They are used to move the cursor, as an alternative to the mouse.
 

 

Monitor

Have you noticed how much your computer screen flickers? This may be because your computer monitor uses CRT technology. This kind of technology offers colour and high-resolution pictures for relatively little money but the monitors are large, use a lot of energy, can flicker and emit electromagnetic radiation.

In recent years flat screens have become increasingly popular. Users talk of benefits such as more desk space, how easy they are to adjust for tilt and height, crisper, clearer images and the total elimination of screen flicker.

It's like having a different PC, they say, a new window on the world.

Most flat screens are based on LCD technology which has a lot of benefits over CRT technology.

Among them:

LCDs are inherently flat, CRT monitors are not, so LCDs require much less space.

 

 

LCDs use less power than CRTs. LCDs are distortion-free while typical CRTs are curved, which may cause image distortion. Most LCD displays use a TFT system offering a wider angle of vision and high-quality images.

But there is one major drawback to flat screens: their cost. They are expensive compared with CRT monitors. Prices are falling, however, and they'll soon find their way into homes, schools and businesses.

Monitor manufacturers like Philips, Apple, Sharp or Panasonic offer compatible flat screens including built-in stereo speakers, headphone connection, and a USB port. Some models can also be removed from the stand and mounted on the wall. They come with stylish designs for a variety of applications.

LCDs range from small-size PC screens and TVs to large-screen projectors.

 

 

Decide whether these statements are true or false:

 

Printer

Dot-matrix printers use pins to print the dots required to shape a character. They print text and graphics and nowadays some of them can print up to 450 characters per second (cps). However, they produce relatively low resolution output - 72 or 144 dots per inch. This level of quality is not recommended for reports or books that have a wide audience. They are slower than laser printers but much cheaper.

 

Laser printers produce output at great speed and with a very high resolution of 600/1,200 dpi. They scan the image with a laser beam and transfer it to paper with a special ink powder. They are constantly being improved. In terms of speed and image quality they are preferred by experts because they have a wider range of scalable fonts and they can emulate different language systems. It goes without saying that they are still expensive.

 

Plotters are a special kind of printer. Plotters use ink and fine pens held in a carriage to draw very detailed designs on paper. They are used for construction plans, engineering drawings and other technical illustrations.

 

We must not forget to mention thermal printers. They use heat, a special kind of paper and electrosensitive methods. They are silent and considered to be inexpensive. However, some colour models that emulate HP (Hewlett Packard) plotters cost too much to be included in the same category.

 

Photosetters can be regarded as an attractive alternative. They do not print on regular paper but on photographic paper or microfilm. They can produce output with a resolution of 2,000 dots per inch. In addition they are extremely fast. Although they produce the highest quality output, they have an important disadvantage: they are the most expensive.

 

Ink-jet printers or bubble-jet printers operate by projecting small ink droplets onto paper to form the required image. This type of printer is quite fast, silent and not so expensive as a laser printer. Nevertheless, you can expect high quality results because most ink-jet printers have a resolution of 720 dpi.

 

 

How to load paper