Output Devices
How does a computer present results, and what makes one output device better than another?
- Define an output device and distinguish softcopy from hardcopy output
- Classify output devices and state the function of each
- Compare printer and display types for a given purpose and budget
Overview
An output device converts processed digital data into a form people (or machines) can use — an image on a screen, ink on paper, sound from a speaker, or movement in a motor. Output is either softcopy (temporary, on screen or through speakers) or hardcopy (permanent, printed on paper or other material).
Softcopy vs hardcopy
Softcopy output disappears when the power goes off or the window closes — a monitor image, a projected slide, a played sound. Hardcopy output is physical and permanent — a printed report, a plotted plan, a 3D-printed part.
Categories of output device
Group them by the sense or action they produce.
Main output devices:
- Display devices: LCD/LED monitors, laptop screens, data projectors, interactive whiteboards — softcopy visual output measured in resolution (e.g. 1920×1080) and refresh rate.
- Printers: Inkjet (photo quality, cheap unit, costly ink), laser (fast, sharp text, low cost per page), dot-matrix (impact — still used for multi-part receipts), thermal (receipts), plotter (large technical drawings), 3D printer (physical objects).
- Audio devices: Speakers, headphones, earphones — convert digital audio signals into sound.
- Actuators & control output: Motors, servos, relays, buzzers and LEDs in robots and embedded systems — output that causes physical movement or signalling.
- Assistive output: Screen readers with speech synthesis, braille displays and embossers, large-print displays.
Choosing a printer
A school office printing 2,000 pages of black text a month should buy a laser printer — fast and low cost per page. A media class printing a few colour posters is better served by an inkjet. A technical drawing class needs a plotter. Always compare cost per page, not just the purchase price.
Devices that do both
Some hardware is both input and output: a touchscreen (displays and senses touch), a multifunction printer (prints and scans), a headset (speaker plus microphone), a network card and a storage drive (data in and out).
Kit out the school on a budget
- Your school has K5,000 for output devices for one computer lab and the front office.
- In groups, list what you would buy (types and quantities) and justify each item.
- Include at least one display device, one printer and one audio device, and state cost per page for your printer choice.
- Present your shopping list in 2 minutes; the class votes for the best value plan.
- Define an output device.
Reveal answer
Hardware that converts processed digital data into a form people or machines can use.
- State the difference between softcopy and hardcopy.
Reveal answer
Softcopy is temporary (on screen or sound); hardcopy is permanent physical output such as print.
- Which printer suits a school printing thousands of text pages, and why?
Reveal answer
A laser printer — it is fast, sharp for text and has a low cost per page.
- Give one example of a device that is both input and output.
Reveal answer
A touchscreen (also a multifunction printer, headset or network card).
- What does a plotter produce?
Reveal answer
Large, accurate technical drawings such as building plans.
Find the cost of one ink cartridge and one toner cartridge in your town, and work out the cost per page for each.