Welcome to Section 2.3: Output Devices and Their Uses!

Hello IGCSE student! In the last section, we learned how to get data *into* the computer (Input). Now, we are going to learn how the computer gets the results *out* to us in a format we can understand—whether it’s on a screen, on paper, or even as physical movement!

Output devices are essential components of any ICT system. Think of them as the translators that convert the computer's digital signals into human-readable information or physical actions.

Key Takeaway from this Introduction:

An Output Device is hardware that displays, prints, or transmits the results of processing from the computer system.

1. Visual and Display Devices

These devices translate the processed data into visual forms—images, videos, or text—that we can view.

1.1 Monitors (Visual Display Units - VDU)

The monitor is perhaps the most common output device. It allows you to see the "soft copy" of your work immediately.

  • Characteristics and Use: Monitors display visual output (text, graphics, video). Modern monitors typically use LED or LCD technology, offering high resolution and clarity.

Advantages:

  • Provides instant feedback and visual proof of processing.
  • Images and text can be updated instantly (dynamic display).
  • Silent operation.

Disadvantages:

  • Output is only a soft copy (it disappears when the device is turned off).
  • Can cause eye strain or headaches if used for prolonged periods.
1.2 Touch Screen (as an Output Device)

"Wait, I thought a touch screen was an input device?" You are right! A touch screen is unique because it is both an input device (when you tap it) AND an output device (when it displays information).

  • Use (Output): It displays menus, images, and feedback, just like a standard monitor. (Think of an ATM screen or your smartphone display.)

Advantage:

  • Highly interactive, combining input and output into one seamless interface.

Disadvantage:

  • If used for output only, it is more expensive than a standard monitor.
1.3 Multimedia Projector

Projectors take the image output from a computer and magnify it onto a large surface, like a screen or wall.

  • Use: Ideal for presentations, classroom teaching, conferences, and showing films to large groups.

Advantages:

  • Allows many people to view the same output simultaneously.
  • Creates very large displays without needing a gigantic monitor.

Disadvantages:

  • Requires a dark room or low light conditions to see the image clearly.
  • Projector bulbs can be very expensive to replace.
  • The image quality can be affected by the projection surface.

Quick Review: Visual Output

Monitors give soft copy feedback. Projectors make it big for a crowd. Touch Screens do both input and output.

2. Hard Copy Output Devices (Printers)

A hard copy is physical output, usually on paper, which remains available even when the computer is turned off.

2.1 Laser Printer

Laser printers are designed for fast, high-quality printing, especially of text and graphics in black and white.

  • Characteristic: They use a fine powder called toner (not liquid ink) and a heated roller (fuser) to permanently bond the toner onto the paper.
  • Use: Printing large volumes of documents in offices or schools.

Advantages:

  • Very fast, especially for bulk printing.
  • Produces very high-quality text and graphics (crisp lines).
  • Cost per page is low for high-volume use.

Disadvantages:

  • High initial purchase price.
  • Toner cartridges and drums can be expensive to replace.
  • Cannot print on multi-part stationary (carbon copies).
2.2 Inkjet Printer

Inkjet printers are common in homes and smaller offices, known for their ability to produce excellent colour photographs.

  • Characteristic: They spray tiny droplets of liquid ink onto the paper through microscopic nozzles.
  • Use: Printing high-quality colour images, photos, and small volumes of general documents.

Advantages:

  • Lower initial purchase cost than laser printers.
  • Excellent quality for colour graphics and photographs.
  • Small physical size, suitable for home use.

Disadvantages:

  • Ink cartridges run out quickly and are expensive (high cost per page).
  • Slower than laser printers, especially for high-volume jobs.

Memory Aid: Think of Inkjet for Ink and Photos; Laser for high-volume Large tasks.

2.3 Dot Matrix Printer

These are often called impact printers because they physically strike the paper.

  • Characteristic: A print head containing a grid of small pins strikes an inked ribbon against the paper to form characters out of small dots.
  • Use: Printing invoices or receipts that require multi-part stationary (e.g., carbon copies) or continuous stationery (e.g., long logs or industrial printouts).

Advantages:

  • Can create multiple copies simultaneously using carbon paper.
  • Very low running costs (ribbons are cheap).
  • Can handle continuous paper feeds (useful for data logging).

Disadvantages:

  • Extremely noisy during operation.
  • Very slow printing speed.
  • Low print quality (the dots are clearly visible).

3. Specialized and Physical Output Devices

These devices perform specific tasks, often related to large-scale design or real-world control.

3.1 Plotters

Think of a plotter as a specialized printer used for huge paper sizes where accuracy is key.

  • Characteristic: They use pens to draw continuous lines rather than dots.
  • Use: Producing large, high-quality engineering drawings, blueprints (architectural plans), and maps (CAD/CAM applications).

Advantage:

  • Can print extremely large formats with high precision and accuracy.

Disadvantage:

  • Very slow compared to standard printers.
  • Typically much more expensive than printers.
3.2 3D Printers

A modern output device that creates three-dimensional physical objects.

  • Characteristic: They use additive manufacturing—layers of material (like plastic filament, resin, or metal powder) are built up layer by layer until the object is complete.
  • Use: Creating rapid prototypes, specialised medical implants (prosthetics), architectural models, and customised parts.

Advantages:

  • Allows for rapid creation of physical models from digital designs.
  • Highly customised items can be produced cheaply and quickly.

Disadvantages:

  • The process can be very slow (takes many hours to print a single object).
  • The materials used can be expensive.

Did you know? 3D printing is revolutionising medicine, allowing doctors to print things like artificial blood vessels and custom tissue structures.

4. Audio and Control Output

Output devices don't just produce visual or paper results—they also produce sound or movement.

4.1 Speakers and Headphones

These devices translate electrical audio signals from the computer’s sound card into audible sound waves.

  • Use: Playing music, system notifications, voice output (e.g., from a navigation system), and alarms.

Advantages:

  • Allows for communication through sound, which is crucial for many applications (media, warnings, communication).
  • Headphones provide privacy and prevent disturbance to others.

Disadvantage:

  • High volume output can cause hearing damage.
4.2 Actuator

An actuator is the computer’s connection to the physical world. It is the component that causes physical movement.

  • Characteristic: An actuator converts electrical energy (the computer signal) into mechanical motion (e.g., opening a valve, moving a robot arm, turning a motor).
  • Use: Crucial in control systems like robotics, automatic security gates, controlling industrial production lines, or adjusting heating valves in a smart home.

Analogy: If the sensor is the computer's 'eye' (input) and the processor is the 'brain', the actuator is the 'muscle' (output). When the computer tells the system to *do* something physical, the actuator carries it out.

Advantages:

  • Enables computers to interact physically with the real world (e.g., factory automation).
  • Can perform tasks that are dangerous or require high precision without human intervention.

Disadvantage:

  • Requires maintenance and can break down due to constant mechanical stress.

Chapter Summary: Output Devices

Output devices take data processed by the CPU and present it in a usable format. When studying for your exam, remember to classify them by their primary function (Visual, Hard Copy, or Control) and be ready to compare their uses, advantages, and disadvantages.

Keep Practising! Try to name an output device for these three tasks: Printing 500 bank statements (Laser Printer), creating a huge map for civil engineers (Plotter), and controlling the temperature in a chicken coop (Actuator). You've got this!