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The Keyboard

A standard PC keyboard has various groups of keys.

Cursor control keys include arrow keys that move the insertion point up, down, right, and left, and keys such as End, Home, Page Up and Page Down, which are used in word processing to move around a long document.

Alphanumeric keys represent letters and numbers, as arranged on a typewriter.

Function keys appear at the top of the keyboard and can be programmed to do special tasks.

Dedicated keys are used to issue commands or to produce alternative characters, e.g. the Ctrl key or the Alt key.

A numeric keypad appears to the right of the main keyboard. The Num Lock key is used to switch from numbers to editing keys.

The Mouse

A mouse is a hand-held device that lets you move a pointer (or cursor) and select items on the screen. It has one or more buttons to communicate to the PC. A scroll wheel lets you move through your documents or web pages. The pointer looks like an I-bar, an arrow or a pointing hand.

An optical mouse has an optical sensor instead of a ball underneath.

A cordless (wireless) mouse has no cable; it sends data via infrared signals or radio waves.

The mouse is widely used in graphics and design. When you want to move an image, you position the pointer on the object you want to move, press the mouse button, and drag the image to a new location on the screen. Similarly, the mouse is used to change the shape of a graphic object. For example, if you want to convert a square into a rectangle, you grab one corner of the square and stretch it into a rectangle.

Voice Input

Today you can also interact with your computer by the voice with a voice-recognition system that converts voice into texts, so you can dictate text directly onto your word processor or email program. You can also control your PC with voice commands, this means you can launch programs, open, save or print files. Some systems let you search the Web or chat using your voice instead of the keyboard.

Scanners

Input devices such as scanners and cameras allow you to capture and copy images into a computer.

A scanner ‘sees’ images and converts the printed text or pictures into electronic codes that can be understood by the computer. With a flatbed color scanner, the paper with the image is placed face down on a glass screen, as with a photocopier. Beneath the glass are the lighting and measurement devices. Once the scanner is activated, it reads the image as a series of dots and then generates the digitized image that is sent to the computer and stored as a file.

The scanner operates by using three rotating lamps, each of which has a different colored filter: red, green, and blue. The resulting three separate images are combined into one by appropriate software.

Barcode scanners read barcodes on the products sold in shops and send the price to the computer in the cash register. Barcodes consist of a series of black and white stripes used to give products a unique identification number.

Digital Cameras

A digital camera doesn’t use film. Photos are stored as digital data (bits made up of 1s and 0s), usually on a tiny storage device known as a flash memory card. You can connect the camera or memory card to a PC and then alter the images using a program like Adobe Photoshop, or you can view the images on a TV set.

Digital Video Cameras and Webcams

A camcorder, or digital video camera, records moving pictures and converts them into digital data that can be stored and edited by a computer with special video editing software. Digital video cameras are used by home users to create their own movies, or by professionals in computer art and video conferencing.

They are also used to send live video images via the Internet. In this case they are called Web cameras, or webcams.

Webcams (short for Web cameras) let you send and receive live video pictures through the Internet. They’re primarily used for video conferences – video calls- but they can be used to record photos and video onto your hard disk.

Ex.1. Answer the following questions:

1. What groups of keys has a standard PC keyboard got?

2. What does a mouse consist of?

3. Where is the mouse widely used?

4. What are the benefits of speech recognition system?

5. Which device is used to input text and graphic images from a printed page?

6. How does a scanner send information to the computer?

7. What is a barcode? How can it be read?

8. How do digital cameras differ from conventional cameras?

9. Which device would you use to take digital video?

Ex. 2. Give the main idea of the text in logical order.

Ex. 3. Translate in writing:

История создания компьютерной мышки.

9 декабря 1968 года первопроходец компьютерных техно-логий Дуглас Энгельбарт (Douglas Engelbart) показал участникам конференции Fall Joint Computer Conference (FJCC) новый способ взаимодействия с компьютером. В своей демонстрации он использовал периферийное устройство, которое можно считать прародителем всех современных компьютерных мышей.

Энгельбарт показал, как с помощью мыши можно вырезать, копировать и вставлять фрагменты текста. Кроме того, была показана возможность совместного доступа к документам по сети. Мышь была частью компьютерной системы NLS. Интересно, что корпус первой мыши был сделан из дерева, а сама она имела всего одну кнопку.

Название «мышь» манипулятор получил в Стенфордском Исследовательском Институте из-за схожести сигнального провода с хвостом одноименного грызуна (у ранних моделях он выходил из задней части устройства). Первым компьютером, в комплект которого включалась мышь, был миникомпьютер XEROX 8010 Star Information System, представленный в 1981 г. Мышь имела три кнопки и стоила 40 долларов США.

За прошедшие годы мыши сильно эволюционировали - появились лазерные, беспроводные модели с большим набором программируемых кнопок. Ежегодно потребителям предлагается огромное количество самых разнообразных мышей - от миниатюрных моделей для использования с ноутбуками до устройств, ориентированных на энтузиастов компьютерных игр. Одна только компания Logitech, которая выпустила свою первую серийную мышь в 1985 году, за прошедшие годы успела отправить потребителям миллиард компьютерных мышек. (BBC News)

Ex. 4. Topics for discussion.

1. Identify the different keys on a keyboard and explain their functions

2. Choose one of the input devices. Describe its functions and features. Try to guess which device your partner is describing.

3. Advantages and disadvantages of digital cameras compared to conventional cameras.

4. The future of speech recognition systems.

UNIT 7

Output Devices

Key vocabulary

1. Instant feedback – моментальная

обратная связь

1. Liquid adj. – жидкий

2. Cathode ray tube – электронно-лучевая

трубка

1. Incorporate v. – включать,

содержать в себе, объединять

1. Consume v. – потреблять,

расходовать

1. Consumption n. – расход,

потребление

1. Color resolution – цветовая

разрешающая способность

1. Axis (pl. Axes) n. – ось, осевая линия

2. Color depth – глубина,

насыщенность света

1. Quantity n. – количество, число,

величина

1. Glow v. – светить, светиться

2. Beam n. – луч, испускаемое

излучение

1. Discharge n. – разряд

2. Angle n. – угол

3. Emit v. – испускать,

выделять, выбрасывать

1. Electroluminescence n. – электролюми-

несценция, электроосвещение

1. Ink-jet printer – струйный принтер

2. Range n. – область, диапазон,

интервал

1. Scalable font – масштабируемый

шрифт

1. Image setter n. – устройство фото-

вывода, система формирования

изображений

Displays

Displays, often called monitors or screens, are the most-used output devices on a computer. They provide instant feedback by showing you text and graphic images as you work or play.

Most desktop displays use Liquid Crystal Display (LCD) or Cathode Ray Tube (CRT) technology, while nearly all portable computing devices, such as laptops, incorporate LSDs. Because of their slimmer design and lower energy consumption, LCD monitors (also called flat panels or flat screen displays) are replacing CRTs.

Basic Features

Resolution refers to the number of dots of color, known as pixels (picture elements), contained in a display. It is expressed by identifying the number of pixels on the horizontal or vertical axes.

Color depth refers to the number of colors a monitor can display. This depends on the number of bits used to describe the color of a single pixel. Monitors with a 32-bit depth are used in digital video, animation and video games to get certain effects.

Display Technologies

An LCD is made of two glass plates with a liquid crystal material between them. The crystals block the light in different quantities to create the image.

A CRT monitor is similar to a traditional TV set. It contains millions of tiny red, green and blue phosphor dots that glow when struck by an electron beam, that travels across the screen and creates a visible image.

In a plasma screen, images are created by a plasma discharge, which contains noble (non-harmful) gases. Plasma TV allow for larger screens and wide viewing angles, making them ideal for movies.

Organic Light-Emitting Diodes (OLEDs) are thin-film LED displays that don’t require a backlight to function. The material emits light when stimulated by an electrical current, which is known as electroluminescence. They consume less energy, produce brighter colors and are flexible – i.e. they can be bent and rolled up when they’re not being used.

Printers

A printer is a device that prints your texts or graphics on paper.

To begin with, you should take into account that printers vary in cost, speed, print quality, and other factors such as noise or printing method.

Dot-matrix printers use pins to print the dots required to shape a character. They can print text and graphics; however, they produce relatively low resolution output – 72 to 180 dots per inch (dpi). They are slower than laser printers, but much cheaper.

An ink-jet (also called bubble-jet) printer generates an image by spraying tiny, precise drops of ink onto the paper. The resolution ranges from 300 to 1,200 dpi, suitable for small quantities or home use.

A standard ink-jet has a three-color cartridge, plus a back cartridge. Professional ink-jets have five-color cartridges, plus black; some can print in wide format, ranging from 60 cm up to 5 meters (e.g. for printing advertising graphics).

Some ink-jet based printers can perform more than one task. They are so called multi-function printers because they can work as a scanner, a fax and a photocopier as well as a printer. Some units accept memory cards and print photos directly from a camera.

Laser printers produce output at great speed and with a very high resolution of 1,200-2,400 dpi. They scan an image with a laser beam and transfer it to paper with a special ink powder called toner. They are constantly being improved. In terms of speed and image quality, laser printers are preferred by experts for various reasons; for instance, they have a wider range of scalable fonts than inkjets, can emulate different language systems, and can produce high-quality graphics.

Thermal transfer printers are used to produce color images by transferring a wax-based ink onto the paper. They are popular for printing bar codes, labels and medium-resolution graphics.

Imagesetters produce very high-resolution output (up to 3,540 dpi) on paper or on the actual film for making the printing plates. In addition, they are extremely fast. Imagesetters are most often used in desktop publishing (DTP).

Ex. 1. Answer the questions:

1. What do CRT and LCD stand for?

2. How are images created in a plasma screen?

3. What are the three advantages of OLED displays?

4. What substance produces light and color when hit with by electrons in CRT monitors?

5. What technology is used in LCDs?

6. What is the importance of “pixel resolution”?

7. What type of computers use LCD displays?

8. Is there a printer that operates by spraying ink droplets onto paper?

9. Is an imagesetter the fastest or the slowest output device?

Ex. 2. Give the main idea of the text in logical order

Характеристики

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