Output DevicesOutput Devices

Output DevicesOutput Devices

►The physical parts of a computer that The physical parts of a computer that you can touch is the you can touch is the hardwarehardware..

►A single item of hardware is called a A single item of hardware is called a devicedevice..

►An output device allows data to be An output device allows data to be displayed or passed out of a computer.displayed or passed out of a computer.

Output DevicesOutput Devices

► PrintersPrinters Laser printerLaser printer Inkjet PrinterInkjet Printer PlotterPlotter

► VDU (Visual Display VDU (Visual Display Unit)Unit) LCD (Liquid Crystal LCD (Liquid Crystal

Display)Display) TFT (Thin Film TFT (Thin Film

Transistor)Transistor)

► Sound CardSound Card► SpeakersSpeakers►Graphics CardGraphics Card► Specialist output Specialist output

devices for disabled devices for disabled users & Virtual users & Virtual Reality.Reality.

Laser PrintersLaser Printers►Can produce black & white images as Can produce black & white images as

well as colour.well as colour.►Do not use ink!Do not use ink!►Use a special powered called Use a special powered called toner.toner.

Inkjet PrintersInkjet Printers

►Quieter than Laser.Quieter than Laser.►High quality prints of both graphics & High quality prints of both graphics &

text.text.►Particularly good at photographic Particularly good at photographic

printoutsprintouts►Can print on different surfaces – CDsCan print on different surfaces – CDs

Photo PrintingPhoto Printing

► Inkjet printers are used to print Inkjet printers are used to print photographs taken by digital camera.photographs taken by digital camera.

►Some have Some have memory cardmemory card slots soslots so

that photos stored on a card can that photos stored on a card can

printed without having to load the printed without having to load the

photos into a computer.photos into a computer.

Comparing PrintersComparing Printers

► If you are going to buy a new printer, If you are going to buy a new printer, what criteria should you use to choose?what criteria should you use to choose?

►ResolutionResolution►SpeedSpeed►CostCost

Capital CostCapital Cost Running CostRunning Cost

ResolutionResolution

►ResolutionResolution is how accurate a printer is. is how accurate a printer is.► It is measured in It is measured in Dots Per Inch (DPI).Dots Per Inch (DPI).

►Laser printers = 300 * 300 dpi to Laser printers = 300 * 300 dpi to about 2400 * 1200 dpi.about 2400 * 1200 dpi.

► Inkjet printers = 360 * 360 dpi to Inkjet printers = 360 * 360 dpi to about 2880 * 270 dpiabout 2880 * 270 dpi

SpeedSpeed

►Speed is measured in Speed is measured in Pages per Pages per MinuteMinute or or PPM.PPM.

► It varies depending on whether you It varies depending on whether you are printing black & white images or are printing black & white images or colour.colour.

►Laser printer are between 4 to 32 PPM.Laser printer are between 4 to 32 PPM.► Inkjet printer are between 2 to 15 PPMInkjet printer are between 2 to 15 PPM

Capital CostCapital Cost

►Laser printer can range from under £100 Laser printer can range from under £100 to more than £2000.to more than £2000.

► Inkjet printer range from £30 to £300.Inkjet printer range from £30 to £300.

►NoteNote this is one part of the situation – this is one part of the situation – the cost to produce a printout is also the cost to produce a printout is also very significant – this is called very significant – this is called running running costscosts..

Running CostsRunning Costs

InkjetInkjet LaserLaser

MonocromeMonocrome ColourColour MonocromeMonocrome ColourColour

CartridgeCartridge £10 - £15£10 - £15 £15 - £25£15 - £25

TonerToner £30 - £50£30 - £50 Up to £200Up to £200

Number of Number of pagespages

500 - 900500 - 900 200 - 500200 - 500 Up to 8000Up to 8000 Up to 3000Up to 3000

Running CostsRunning Costs

►Laser printer use more electricity than Laser printer use more electricity than inkjets.inkjets.

►Running costs can increase if labels, Running costs can increase if labels, envelopes and photo quality paper are envelopes and photo quality paper are used.used.

► Inkjet printers can be bought so cheaply Inkjet printers can be bought so cheaply because the makers know people will because the makers know people will have to pay for ink.have to pay for ink.

►Petrol = £1.40 per litre. Ink = £1700 Petrol = £1.40 per litre. Ink = £1700 per litre! per litre!

MonitorsMonitors

►Accepts a video signal directly from Accepts a video signal directly from a computer.a computer.

►Three Main types of monitor are:Three Main types of monitor are: Cathode Ray Tube (CRT)Cathode Ray Tube (CRT) Liquid Crystal Display (LCD)Liquid Crystal Display (LCD) Thin Film Transistor (TFT)Thin Film Transistor (TFT)

Cathode Ray Tube (CRT)Cathode Ray Tube (CRT)

►Large, Heavy, power and Large, Heavy, power and

space consuming.space consuming.

Liquid Crystal Display (LCD)Liquid Crystal Display (LCD)

►Can have as many as 2.3 million pixels Can have as many as 2.3 million pixels which have to be switched on and off which have to be switched on and off individually.individually.

►Used for small, low resolution devices Used for small, low resolution devices like calculators & watches.like calculators & watches.

Thin Film Transistor (TFT)Thin Film Transistor (TFT)►This gives improved clarity and This gives improved clarity and

colour.colour.►High quality colour displays on High quality colour displays on

laptops & desktops.laptops & desktops. Smaller and lighter than CRTSmaller and lighter than CRT Use less power – good for portable Use less power – good for portable

devicesdevices However, they have a limited viewing However, they have a limited viewing

angle and are expensive to produce.angle and are expensive to produce.

MonitorsMonitors

Speakers Speakers

►Most computers have built in Most computers have built in speakers.speakers.

Sound CardSound Card► Improves the quality of sound Improves the quality of sound

outputted from the computer for outputted from the computer for games, multimedia applications, CDs games, multimedia applications, CDs and DVDs.and DVDs.

►Allows sound to be input via a Allows sound to be input via a microphone.microphone.

►The sound card does The sound card does Digital toDigital to

analogue conversion.analogue conversion.

Graphics CardGraphics Card

► Controls the quality Controls the quality of the display on a of the display on a monitor.monitor.

► Can contain a large Can contain a large amount of RAM.amount of RAM.

►May have its own May have its own processor.processor.

Specialist Output DevicesSpecialist Output Devices

►Computers can be used to output voice Computers can be used to output voice (speech synthesis).(speech synthesis).

►Useful for users with a visual impairment.Useful for users with a visual impairment.►Multimedia projectorMultimedia projector

►Virtual RealityVirtual Reality Users wear a headset with Users wear a headset with

earphones.earphones.