Hardware

Lesson 5

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StarterName these devices and explain if they are input or output devices.

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Objective of the LessonDescribe suitable output devices for a wide range of computer controlled

situations.

• All of you will:– Identify 3 different output devices and explain how they are used.

• Most of you will:– Describe how the most common types of output devices work.– Create a presentation to explain which output device would be

most suitable for different situations.

• Some of you will:– Explain the advantages and disadvantages of the output devices

they identify.

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• Everybody should complete the presentation they start at the end of this lesson.

• Some of you may also want to get the extra marks by answering the questions on the worksheet.

• This homework is due in next lesson.

• Make sure you have written your homework clearly in your planner.

Homework

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Inputting Data• There are several ways in which data can be

inputted into a system.• We have looked at using sensors and many manual

input devices such as keyboards, mice and scanners.

• There are other ways that data can be inputted and these include:– Optical Mark Recognition (OMR)– Optical Character Recognition (OCR)– Magnetic Ink Character Reading (MICR)

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Optical Mark Recognition (OMR)• The most popular use of OMR in the

UK today is with Lottery tickets. • Users make a mark on the pre-printed

paper that is then fed into a machine where a laser reads where the marks are and then it prints out your ticket.

• This type of technology is also used on multiple choice quizzes and tests.

• OMR is a fast and accurate way of entering numbers and greatly reduces the risk of inputting the data incorrectly.

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Optical Character Recognition (OCR)• Optical Mark Recognition simply reads

where the marks are on the pre-printed paper. Optical Character Recognition is more complex and is used to read and understand handwriting and identify the common shapes of letters.

• This is commonly used in the Post Office sorting rooms where the postcodes are read very quickly so the letters can be directed to the correct area for sorting and delivery.

• This type technology is much more complex and therefore more expensive.

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Optical Character Recognition (OCR)• A similar type of technology is

now being used in smart phones and tablets where the user can write on the touchscreen and then the device translates this into typed text.

• OCR is also used in text scanners where typed documents are fed in which are scanned and then the text is translated and saved in a document.

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Magnetic Ink Character Recognition (MICR)• At the bottom of a standard cheque are a group of

numbers printed using magnetic ink.

• A special reader is used to read these numbers and it will ignore any parts which may have been written in another type of ink.

• This helps defend against fraud where people may alter the look of thenumbers to take the money out of a different bank account.

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Recap what you have learnt so farWork in pairs to answer these questions:

1. What does OMR stand for and how does it work?

2. What does OCR stand for and how does it work?

3. What does MICR stand for and how does it work?

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Output DevicesSo far we have looked at input devices, we are now going to look at common output devices

that are used today.

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Monitor• Monitors are the most common

output devices used today and are used to display what’s happening on your computer.

• The images on the monitor are made up of individual dots called pixels.

• The higher the number of pixels, the better quality the screen would be.

• This is known as the “Resolution”.

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Speakers, Headphones and Earphones

• Most modern computers are fitted with a “Sound Card” which allow output devices to be attached that will allow the user to play sound through the computer.

• The higher quality the speakers, headphones or earphones the more expensive they tend to be.

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Printers• There are several types of printer available and these

include:– Laser Printers– Ink-Jet Printers– Dot-Matrix Printers– Plotters

• All of them create a “hard copy” of the output which means that they produce a print out.

• Most print onto paper but some are also produced which print labels on CDs or DVDs and others on fabric.

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Laser Printer• Laser printers are used in offices as

they are relatively quiet and fast.• They use coloured powdered inks

(known as a toner), which is placed on the paper and then heated up using a laser to bond the ink to the page.

• Black and white laser printers are relatively cheap but the toners can be expensive.

• A laser printer produces high quality printing which is close to photographic quality.

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Ink-Jet Printer• Ink-Jet printers work by firing droplets of

ink out of tiny nozzles which is why the output of an ink-jet printer can often be slightly wet which can be easily smudged.

• Colour ink-jet printers are often used for home users where they do not need so many documents.

• Colour printing can be slow but the printer itself is very cheap and a good quality colour ink-jet printer can cost under £30.

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Dot-Matrix Printer• Dot-matrix printers are known as

“impact printers”. They use tiny pins to form the shape of a character which are used to hit a carbon ribbon and then the paper.

• They are noisy and are not used much these days but can still be found in garages where a robust simple printer is used to print out MOT certificates and invoices for clients.

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Plotter• A plotter is a type of printer that uses pens, controlled

by motors to move across large sheets or paper.• These are commonly used by architects and engineers

to create high quality large plans.• There are two main types of

plotter: – flat bed which holds

the paper still and moves thepen.

– drum which rotates the paper around a roller.

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Touchscreen• This type of device is both an input device and an output

device.• You can use your fingers to control the device and select

options and also you can use the screen to see what is happening.

• Touchscreen technology is becoming more common as it is easy to use. Common uses include:

– Smart phones– Tablets– GPS systems in cars– Screens on digital cameras and video– Laptops

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Your TaskCreate a presentation to explain which device would be most suitable for the following scenarios. Describe the advantages and disadvantages of each type of device and explain how it works.1. A local window cleaner wants to produce some colour flyers to

advertise his company but does not want to spend too much.2. A builder wants to print out the plans for a new house he is

building.3. A student wants to be able to listen to music from his laptop while

he is working in the library.4. A company want to make a new mobile phone which is easy to use.5. A car dealership company wants to print out the history of a car

they are selling.