Input and Output Devices (SRAS ICT1)

Input and Output Devices (SRAS ICT1)

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  Input and Output Devices
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  What Is AnInput Device? • Entering data or instructions into a computer is called input. • Therefore, an input device is a device which enters data or instructions into a computer. • Input devices are necessary to convert data into a form which can be understood by computers.
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  Some input devicesare:
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  The Joystick • Ajoystick looks like a stick fixed onto a box. • It controls the cursor on the screen, so we can say it is alternate to the mouse.
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  The Mouse • Thisinput device controls the cursor on the computer screen. • It has two or three buttons and a cable connecting it to the computer. • It is quite easy to operate a mouse, the user simply moves the cursor along the table. • Once the cursor is at the desired location, the user can give instructions to the computer by clicking the button.
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  The Keyboard • Keyboardscome in different shapes and sizes depending on the type of brand. They are similar to typewriters.
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  The Scanner • Thislooks like a photocopying machine, its function is to scan any document placed on its flat glass and send the contents to the computer.
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  The Bar CodeReader • The black and white lines printed on certain products which represent information like the country of origin, the price of it etc are bar codes. • They can be read by a bar code reader which are commonly used in Supermarkets and shops.
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  What is anOutput device? • The information we get from the computer is known as output. • The computer presents this information through these devices such as:
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  The Monitor • Themonitor is one of the most important output devices, it is used to display text and pictures. • The monitor is also known as the Visual Display Unit (VDU)
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  The Printer There areseveral types of printers, some are: • Dot matrix- Consists of a print head with a number of pins which move in and out to print in the form of dots. • Ink- jet- Consists of a print head with a number of tiny nozzles and coloured ink to form tiny dots. • Laser- Prints images by transferring ‘ ink powder’ onto a piece of paper using a laser beam.
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  The Plotter • Aplotter produces its output using special pens across the paper to create a drawing. • Engineers, architects and designers use plotters to produce their drawings or designs.
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  The Microfilm • Thecomputer can also output its data on film. A microfilm is a film available in the form of reels while card-sized sheets are called microfiche. Large amounts of data can be stored this way.
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  Processors Micro processo rs
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  Memory RAM mor y Ca ch e Me
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  Storage Devices Flo ppy Mem Dis ory k Key o m CD R