ICT 0417 – Types and Components of Computer Systems: Input and Output Devices
Types and Components of Computer Systems
Objective
Know and understand the differences between input and output devices.
1. What are Input Devices?
Input devices allow users to enter data, commands, or instructions into a computer system. They convert physical signals (such as sound, light, or motion) into digital information that the computer can process.
Keyboard – types alphanumeric characters.
Mouse / Touchpad – controls pointer movement and selects items.
Scanner – converts printed text or images into digital files.
Microphone – captures audio signals.
Digital Camera – captures still images and video.
Joystick / Gamepad – provides directional control for games and simulations.
Touchscreen – combines input and output; registers finger pressure as input.
2. What are Output Devices?
Output devices present processed data from the computer to the user in a usable form. They transform digital information into visual, audible, or tactile signals.
Monitor / Display – shows visual information (text, graphics, video).
Printer – produces hard‑copy documents and images.
Speakers / Headphones – reproduce audio output.
Projector – enlarges visual output onto a screen or wall.
Plotter – draws high‑precision graphics on paper.
Haptic devices – provide tactile feedback (e.g., vibration in game controllers).
3. Comparison of Input and Output Devices
Aspect
Input Devices
Output Devices
Primary Function
Enter data/commands into the computer
Present processed data to the user
Signal Direction
External → Computer
Computer → External
Typical Examples
Keyboard, mouse, scanner, microphone
Monitor, printer, speakers, projector
Data Type Handled
Raw, unprocessed data (e.g., keystrokes, sound waves)
Processed data (e.g., formatted text, images, audio)
User Interaction
Active – user initiates input
Passive – user receives output
Conversion Process
Analog → Digital (e.g., microphone)
Digital → Analog/Visual (e.g., speaker, monitor)
4. Combined Input/Output Devices
Some devices perform both functions, acting as both input and output mechanisms.
Touchscreen – displays information (output) and detects touch (input).
All‑in‑One printers – can scan documents (input) and print them (output).
Interactive whiteboards – show presentations (output) and detect pen or finger gestures (input).
5. Summary Checklist
Identify whether a device is primarily used for input, output, or both.
Know at least three examples of each type.
Understand the direction of data flow for each device.
Recognise the conversion process (analog ↔ digital) involved.
6. Quick Quiz
Answer the following questions to test your understanding.
Which device converts sound waves into digital data? Answer:
Is a printer an input or output device? Explain why. Answer:
Give two examples of devices that can act as both input and output. Answer:
What is the main difference in data flow between a keyboard and a monitor? Answer:
Suggested diagram: Flow of data from input device → CPU → output device, showing conversion steps (analog‑to‑digital and digital‑to‑analog).