OUTPUT DEVICES MONITORS

Transcription

1 OUTPUT DEVICES MONITORS Task 1 Describe the monitor of your computer Is it a monochrome or a colour monitor? What size is the screen? Does it have a cathode ray tube or a flat LCD screen? How can you change the picture using the controls? Does it produce a high quality image? Can you watch TV on your PC monitor? Task 2 Complete these definitions with listed words. Then read the text and check your answers. resolution pixel aspect ration colour depth video adapter plasma screen 1. the smallest unit on a display screen or bitmapped image (usually a coloured dot) is called 2. an expansion card that generates the video signal sent to a computer display is called 3. the width of the screen in proportion to its height is called 4. also called gas discharge display - 5. the number of pixels contained in a display, horizontally and vertically is called 6. the number of bits used to hold a colour pixel; this determines the maximum number of colours that can be displayed How do screen displays work? Displays, often called monitors or screens are the most used output devices on a computer. They provide instant feedback by showing your 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 LCDs. Because of their slimmer design and lower energy consumption, LCD monitors (also called flat panel or flat screen displays) are replacing CRTs. 1

2 Basic features Resolution refers to the number of dots of colour, known as pixels (picture element), contained in a display. It is expressed by identifying the number of pixels on the horizontal and vertical axes. A typical resolution is 1024x768. The sharpness of images is affected by dot pitch, the distance between the pixels on the screen, so a dot pitch of 0,28 mm or less will produce a sharp image. Two measurements describe the size of your display: the aspect ratio and the screen size. Historically, computer displays, like most televisions, have had an aspect ratio of 4:3 the width of the screen to the height is four to three. For widescreen LCD displays, the aspect ratio is 16:9, very useful for viewing DVD movies, playing games and displaying multiple windows side by side. High-definition TV also uses this format. The viewable screen size is measured diagonally, so a 19 screen measures 19 from the top left to the bottom right. Inside the computer there is a video adapter, or graphics card, which processes images and sends signals to the monitor. CRT monitors use a VGA (video graphics adapter) cable, which converts digital signals into analogue signals. LCD monitors use a DVI (digital video interface) connection. Colour depth refers to the number of colours a monitor can display. This depends on the number of bits used to describe the colour of a single pixel. For example, an old VGA monitor with 8-bit depth can generate 256 colours and a Super VGA with a 24-bit depth can generate 16.7 million colours. 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 the liquid crystal material between them. The crystals block the light in different quantities to create the image. Active-matrix LCDs use TFT (thin film transistors) technology, in which each pixel has its own switch. The amount of light the LCD monitor produces is called brightness or luminance, measured in cd/m2 (candela per square metre) A CRT monitor is similar to a traditional TV set. Inside the tube there is an electron beam which scans the screen and turns on or off pixels that make up the image. The beam begins in the top left corner and scans the screen from left to right in a continuous sequence, similar to movement of our eyes when we read, but much faster. This sequence is repeated 50, 70 or 85 times per second, depending on the system. If the rate of repetition is low, we perceive a flickering, unsteady screen, which can cause eye fatigue. However, fast-moving 75 Hz refresh rate eliminates this annoying flicker. On colour displays there are three electron guns at the back of the monitor s tube. Each gun shoots out a beam of electrons for each of the primary colours. These electrons strike the inside of the screen which is coated with substances called phosphors that glow when struck by electrons. PCs can be connected to video projectors, which project the image onto a large screen. They are used for presentations and home theatre applications. In a plasma screen, images are created by a plasma discharge which contains nonharmful gases. Plasma TVs 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 simulated by an electrical current, which is known as electroluminescence. They consume less energy, produce brighter colours and are flexible i.e. they can be bent and rolled up when not being used. 2

3 Task 3 Read the text again and answer these questions. 1. According to the writer, what is the importance of 'pixel resolution'? 2. Which unit of frequency is used to measure the refresh rate of a monitor? 3. In the writer's opinion, why can a low refresh rate produce eye fatigue? 4. What substance is hit by electrons in a monitor? 5. What is the standard display system for many PCs? 6. What does 'LCD' stand for? 7. What type of computers use LCD displays? Tables often include abbreviations and technical words that are not easy to understand. Look at this table and the explanation of Monitor A's specifications. The specifications of Superview (Monitor A) may be explained like this: 1. This is a flat-panel Liquid Crystal Display. 2. The screen size is 1801 inches (diagonal viewable image size). 3. You get a resolution of 1024 by 768 pixels. 4. It offers support for 1607 million saturated colours. 5. This digital display has a 75 hertz refresh rate. 6. It never flickers (the images are bright, sharp, and distortion-free). 7. You can change the orientation of the display, adjusting your viewing angle back and forth. 8. It has a built-in power feature that saves a lot of energy consumption. Use the example above to help you describe Monitor B. 3

4 Language work: Instructions and advice Task 4 Look at the HELP box above and then rewrite the sentences below about what you should do to protect your eyes. Use modal auxiliary verbs in your sentences. 1. Do not stare at the screen for long periods of time. 2. Avoid placing the monitor so that it reflects a source of bright light, such as a window. 3. Keep the screen clean to prevent distorting shadows. 4. lf you work in an office with a large number of computers, don't sit too close to the sides or backs of the monitors. 5. Buy a protective filter that cuts down the ELF (extremely low frequency) emissions. (taken from: Santiago Remacha Esteras, «Infotech», Cambridge University Press 2008) 4

5 GRAMMAR WORK MODAL VERBS All the auxiliary verbs except be, do and have are called modals. Unlike the other auxiliary verbs, modals only exist in their helping form; they cannot act alone as the principle verb in a sentence. Be, do, and have differ from the other auxiliaries in that they can also serve as ordinary verbs in a given sentence. The Modal verbs are: CAN / COULD / MAY / MIGHT / MUST / SHALL / SHOULD / OUGHT TO / WILL / WOULD Modal Example Uses Can Could They can control their own budgets. We can t fix it. Can I smoke here? Can you help me? Could I borrow your dictionary? Could you say it again more slowly? We could try to fix it ourselves. I think we could have another Gulf War. Ability / Possibility Inability / Impossibility Asking for permission Request Asking for permission Request Suggestion Future possibility May He gave up his old job so he could work for us. May I have another cup of coffee? Ability in the past Asking for permission China may become a major economic power. Future possibility Might They might give us a 10% discount. Future possibility Must We must say good-bye now. They mustn t disrupt the work more than necessary. Necessity / Obligation Prohibition We ought to employ a professional writer. Ought to Saying what s right or correct 5

6 Shall (More common in the UK than the US) Should ProgramiranjeI_sylabus.doc Shall I help you with your luggage? Shall we say 2.30 then? Shall I do that or will you? We should sort out this problem at once. I think we should check everything again. Profits should increase next year. I can t see any taxis so I will walk. Offer Suggestion Asking what to do Saying what s right or correct Recommending action Uncertain prediction Instant decisions Will I will do that for you if you like. I will get back to you first thing on Monday. Offer Promise Profits will increase next year. Certain prediction Would you mind if I brought a colleague with me? Asking for permission Would you pass the salt please? Request Would Would you mind waiting a moment? Request "Would three o clock suit you?" - "That d be fine." Making arrangements Would you like to play golf this Friday? "Would you prefer tea or coffee?" - "I d like tea please." Invitation Preferences Note: The modal auxiliary verbs are always followed by the base form. 6

7 MUST vs. HAVE TO Both must and have to can be used to speak about obligation or necessity: The doctor says I must stop smoking. The doctor says I have (got) to stop smoking. This is only the case when we are referring to the present or future. When we speak about obligation or necessity in the past, we use have to. She had to stop running because she was exhausted. I had to pay a parking fine. (It is not possible to use must in this way.) Also, must and have to can both be used to express the idea of certainty: He must be the fastest runner in the world. He has (got) to the fastest runner in the world. To speak about certainty in the past, we use must: He must have been late because I saw him miss the train. The storm must have spoilt their picnic. (It is not possible to use have to in this way.) When used in the negative, must and have to have different meanings. Must is used to say that something is prohibited, while have to is used to express a lack of obligation: You mustn't cross the road here. (It is prohibited) You don't have to cross the road here. (It's not necessary, i.e. you can stay on this side and cross later). 7

8 EXERCISES: ProgramiranjeI_sylabus.doc Task 1 Decide which type of modal goes with each sentence and then fill in the gaps with have to, must, should or ought to. When you see negative, the modal verb must be in a negative form. 1. If you want to lose weight, you eat pasta, potatoes, white bread or white rice. (negative) 2. It's alright. You _ come to Muriel's wedding if you don't want to. (negative) 3. Silly boy! You play with matches! (negative) 4. I haven't heard from Eleonora for ages. Maybe I give her a ring. 5. You _ remember your passport. Otherwise they won't let you on the plane. 6. The weather forecast says this weekend will be fine. We go on a picnic. 7. You _ go there on your own. It's extremely dangerous. (negative) 8. You _ come if you don't feel like it. (negative) 9. You _ take life so seriously. Relax a bit. (negative) 10. Orange juice in cartons has no goodness in it at all. You make it yourself. 11. You _ drink and drive. (negative) 12. These instructions are difficult to follow. They to explain things better. Task 2 Complete these sentences. Use have to, needn t or mustn t. 1. We buy any disks. We ve got enough. 2. You _ use a monitor that is fuzzy or distorts the image. 3. In the UK, many students _ wear a uniform at school. 4. Sarah send this fax. The boss told her to. 5. You _ touch that switch; it s dangerous. 6. You _ pay for this, it s free. Task 3 Which sentences have a similar meaning? 1. You have to be back home at You don't have to be back home at You must be back home at You needn't be back home at 10. 8

9 Task 4 ProgramiranjeI_sylabus.doc Fill in the gaps with the appropriate form of MUST or HAVE TO. 1. I be at the meeting by 10:00. I will probably take a taxi if I want to be on time. 2. You submit the application if it has not been completely filled out. Check that the name, address, and background information are correct. If the form is not accurate and complete, you will be rejected and you will reapply at a later date. 3. A: Look at these flowers - they're beautiful! But, there's no card. Who could have sent them? B: It have been David. He's the only one who would send you flowers. 4. You forget to pay the rent tomorrow. The landlord is very strict about paying on time. 5. You be so rude! Why don't you try saying "please" once in a while. 6. If you are over 18 in California, you take a driver training course to get a driver's license. You can have a friend or a family member teach you instead. But remember, you still get your permit before you start practicing. 7. You be rich to be a success. Some of the most successful people I know haven't got a penny to their name. 8. A: My car broke down in Death Valley last week. I have it towed more than a hundred miles to the nearest mechanic. B: That have cost a fortune! 9. While hiking in Alaska, you keep an eye out for bears. If you see one, you approach it. They are beautiful animals; however, they are wild and unpredictable in nature. You the dangers can help keep you safe. be afraid of them, but educating yourself about 10. I go to work tomorrow because it is Memorial Day. The best thing about a day off from work is that I to. get up at 6:00; I can sleep in till noon if I want 11. Yesterday, I cram all day for my French final. I didn't get to sleep until after midnight. 9

10 12. A: Oh no! I completely forgot we were supposed to pick Jenny up at the airport? B: She still be sitting there waiting for us. 13. Ingrid received a scholarship to Yale University which will cover 100% of the tuition. She worry at all about the increasing cost of education. 14. I've redone this math problem at least twenty times, but my answer is wrong according to the answer key. The answer in the book be wrong! Task 5 Complete the following sentences with an appropriate modal verb. 1. If you type a lot at your computer each day, you buy and ergonomic keyboard; it can help reduce the risk of repetitive strain injury. 2. You place your mouse within easy reach and support your forearm. 3. If you decided to build your own PC, protect yourself from electric shocks. You touch any components unnecessarily. 4. You always use a copyholder if you are working from documents. The best position is between the screen and the keyboard, or at the same height as the screen; this can reduce neck, back and eyestrain. 5. Irresponsible disposal of electronic waste can cause severe environmental and health problems. You just throw your old monitor or video system into the bin. 10

11 KEY TO GRAMMAR EXERCISES Task 1 1. must not 2. don t have to 3. must not 4. should 5. must not 6. should 7. don t have to 8. should not 9. should 10. must not 11. ought Task 2 1. needn t 2. mustn t 3. have to 4. has to 5. mustn t 6. don t have to Task 3 Sentences 1 and 3 are similar as well as sentences 2 and 4. Task 4 1. must - have to 2. mustn't have to 3. must 4. mustn't 5. mustn't 6. don't have to must 7. don't have to 8. had to - must 9. must mustn't don't have to 10. don't have to don't have to 11. had to 12. must 13. doesn't have to 14. must 11

12 Task 5 1. If you type a lot at your computer each day, you should buy and ergonomic keyboard; it can help reduce the risk of repetitive strain injury. 2. You should place your mouse within easy reach and support your forearm. 3. If you decided to build your own PC, protect yourself from electric shocks. You mustn t/shouldn t touch any components unnecessarily. 4. You ought to/should always use a copyholder if you are working from documents. The best position is between the screen and the keyboard, or at the same height as the screen; this can reduce neck, back and eyestrain. 5. Irresponsible disposal of electronic waste can cause severe environmental and health problems. You shouldn t/mustn t just throw your old monitor or video system into the bin. 12