Unit 3: Understanding ICT Systems in Everyday Life Flashcards
Give examples of Input Devices? (9)
Keyboard, mouse, tracker pad, joystick, touch screen, microphone, scanner, digital camera + graphics digitiser.
Give examples of Output Devices? (6)
Visual Display Unit (VDU), Impact Printer, Laser Printer, Inkjet Printer, Plotter + Speaker.
Talk about:
Keyboards
Uses standard layout (QWERTY) Depends on human for input speed. Prone to human error. Used to enter text into computer. Some are designed for certain applications (EPOS + ATM) Fewer keys + emphasis on numeric keys.
What are concept keyboards?
Have keys with pictures/words that can be programmed to carry out certain instructions.
Talk about:
Tracker Pads
Known as touch sensitive pad.
Used as alternative to mouse on laptop.
Ideal for portable device as fine for confined space.
Movement on pad controls cursor, allowing user to select options from menus, select icons + position cursor.
Talk about:
Mouse
Referred to as ‘pointing device’, easy to use + inexpensive, designed to fit under hand, can contain 2 or 3 buttons for selection, slower than using ‘hot keys’, some use mouse ball + built-in movement, others use infared or wireless.
Talk about:
Joystick
Control object on screen by manoeuvring small lever in diff directions, senses movements converted to co-ordinates, has pre-programmed buttons to allow actions to be carried out + used to play computer games.
Talk about:
Touch Screen
Reacts to human touch, minimal user training, no add hardware, more expensive than LCD, used in banks, tourist offices, museums + supermarkets, used in hand-held consoles, PDAs + mobile telephones.
How does a touch screen work?
When user’s finger touches screen, vertical + horizontal light beams are sensed + converted into a co-ordinate. To perform ‘drag and drop’ operations, drag finger across the screen.
Talk about:
Microphones
Input sound/human voice into computer system, used in voice-recognition applications, natural communication form for humans, background noise can interfere, can record music + store in digital format.
Spoken word can be converted to text/computer can interpret spoken commands. Voice recognition useful for those with less mobility.
Talk about:
Scanner
Converts hard copy of pics/text into digital image. Beams of light passed over image which is recognised as series of dots on page.
Once scanned, can be saved + edited, if text scanned can be recognised by word processor using OCR then can be edited + saved, quality measured in dpi. Cheap scanners up to 2400 x 4800 dpi up to A4.
Talk about:
Digital Camera
Stores pics on memory card, small LCD screen attached to view pics, can be downloaded to computer by USB cable/wireless connection.
Can capture short vid clips that last couple mins.
How much does a typical memory card store?
4 GB, around 1000 pics in medium resolution.
Talk about:
Graphics Digitiser
Flat electronic sensitive surface that captures image drawn with stylus pen, allows user to record hand-drawn image in computer system + image drawn can be imported to graphics package for further editing.
Talk about:
Visual Display Unit (VDU)
Displays info/output from computer on screen. Made up of pixels, cost of monitor increases as size + resolution get bigger, LCD screen is lighter + smaller than typical desktop CRT screen, LCD require less power, some have inbuilt speakers + microphones + Modern VDUs have inbuilt filtering system to reduce eyestrain.
What is a pixel?
Smallest area on screen that can be edited. Pic is made up of pixels.
What is screen resolution?
Measure of the quality of an image on screen. More pixels, higher resolution.
Talk about:
Impact Printer
Print head made up of pins in rows + columns (matrix). Print head strikes ink ribbon leaving impression on page, characters formed as series of dots. More pins, better quality. Useful for carbon copies (invoices), prints in 1 colour, costs less than to print multiple copies (carbon copies), low quality, noisy.
Talk about:
Laser Printer
Non-impact printer, uses toner, some are 3in1 for scanner, photocopier + fax, usually have own memory here pages stored before printing, black+white/colour, suitable for high vol printing, good quality + high speed.
Talk about:
Inkjet Printers
Non-impact, black+coloured cartridges, ink heated + sprayed through nozzles/jets in print head, black+white/colour, print pics/low vol printing, high quality print, slower.
Talk about:
Plotters
Some use electronically controlled pens, others penless (raster) plotters, high quality, accurate + detailed diagrams, used by architects, surveyors, pattern makers + engineers, variety of paper size (A0), draws diff characters of diff sizes + fonts to add to drawings.
Talk about:
Speakers
Small internal speakers standard in computers, provides sound output through sound card, output music + spoken word, useful for visually impaired users + draws attention to input error.
How is memory measured on a computer?
What is the smallest unit of storage?
Bits + bytes 1 bit (binary digit) 1 or 0
1 byte = x bits 1 kilobyte (KB) = x bytes 1 megabyte (MB) = x kilobytes 1 gigabyte (GB) = x megabytes 1 terabyte (TB) = x gigabytes
8 bits 1024 bytes 1024 kilobytes 1024 megabytes 1024 gigabytes