Input device
A physical component or device that is used to feed data and instructions to the computer
Why are input devices required?
They allow users to interact with and provide data for the computer to process.
Keyboard - how it works + function + examples + advantage/disadvantage
Function: Enters text, numbers, and commands
How it works: Each key press sends a unique binary signal to the computer
Uses: Writing documents, entering data
Advantage: Simple and widely used
Disadvantage: Can be slow for large data entry; prone to typing errors
Optical Mouse - how it works + function + examples + advantage/disadvantage
Function: Controls pointer movement on a screen
How it works: A small camera under the mouse detects changes in surface movement
Uses: Navigation and control in user interfaces
Advantage: Fast and accurate
Disadvantage: Doesn’t work well on some shiny or transparent surfaces
Microphone -how it works + function + examples + advantage/disadvantage
Function: Converts sound waves into electrical signals.
How it works: Sound vibrations are detected by a diaphragm and converted into digital audio data.
Uses: Voice recognition, video calls, sound recording.
Advantage: Enables voice input.
Disadvantage: Can pick up background noise.
Touchscreen - how it works + function + examples + advantage/disadvantage
Function: Allows user to interact by touching the display.
How it works:
Resistive: Two layers touch when pressed, detecting position.
Capacitive: Detects electrical current from finger touch.
Infra-red: Uses light beams; touch breaks the beams.
Uses: Smartphones, ATMs, kiosks.
Advantage: Easy to use, no need for separate input devices.
Disadvantage: Can get dirty; may need calibration.
Barcode scanner - how it works + function + examples + advantage/disadvantage
Function: Reads barcodes (patterns of black and white lines) on products.
How it works: Shines a laser on the barcode; the light reflected back is converted into digital data.
Uses: Supermarket checkouts, inventory management.
Advantage: Fast and accurate data entry.
Disadvantage: Barcode can get damaged or smudged.
3 touch screen types
Resistive: Two layers touch when pressed, detecting position.
Capacitive: Detects electrical current from finger touch.
Infra-red: Uses light beams; touch breaks the beams.
QR code scanner - how it works + function + examples + advantage/disadvantage
Function: Reads QR codes (square barcodes with encoded data).
How it works: Camera scans the code; software decodes the information.
Uses: Payments, ticketing, marketing links.
Advantage: Can store more data than a barcode.
Disadvantage: Needs camera access and proper lighting.
Digital camera - how it works + function + examples + advantage/disadvantage
Function: Captures still or moving images.
How it works: Light enters through a lens, hits an image sensor (CCD or CMOS), and converts it into digital data.
Uses: Photography, security systems, facial recognition.
Advantage: Produces high-quality images quickly.
Disadvantage: File sizes can be large; may need memory cards.
2d and 3D scanners - how it works + function + examples + advantage/disadvantage
Function: Captures the image or shape of an object.
How it works:
2D Scanner: Scans flat images (like documents).
3D Scanner: Scans the shape and depth of an object using lasers or sensors.
Uses: 2D for document scanning; 3D for design, medical imaging, gaming.
Advantage: Accurate reproduction of objects.
Disadvantage: 3D scanners can be expensive.
Output device
hardware components that receive information from a computer system and present it to the user in an understandable form
Why are output devices required
They allow uses to see, hear, or physically experience the results of computer processing
Sensor
Device that detects or measures physical properties and converts them into data for a computer
What are sensors used for
The collect data automatically from the environment without human input
What type of data does a sensor capture
Analogue data
- temp, light, sound
How is sensor data used in computers
It is converted into digital data and used to monitor or control systems
- turning on lights, adjusting temp
Actuator - how it works + function + examples + advantage/disadvantage
Function: Converts electrical signals into physical movement.
How it works: Receives signals from a computer and produces motion (e.g. by rotating, opening, or pushing).
Uses: Automatic doors, robotics, temperature control systems.
Advantage: Enables computers to control physical processes automatically.
Disadvantage: Can wear out or malfunction mechanically.
Digital light processing (DLP) projector - how it works + function + examples + advantage/disadvantage
Function: Projects digital images onto a large screen.
How it works: Uses tiny mirrors and a spinning colour wheel to reflect light and form images on a screen.
Uses: Classrooms, cinemas, presentations.
Advantage: Produces bright, high-quality images.
Disadvantage: Can be expensive; needs regular maintenance (e.g. bulb replacement).
Inkjet printer - how it works + function + examples + advantage/disadvantage
Function: Prints text or images by spraying tiny droplets of ink onto paper.
How it works: Print head moves across paper, releasing ink through nozzles.
Uses: Home and small office printing.
Advantage: High-quality color printing; relatively cheap.
Disadvantage: Slow for large volumes; ink cartridges can be costly.
Laser printer - how it works + function + examples + advantage/disadvantage
Function: Produces high-quality printed documents quickly.
How it works: Uses a laser beam to form an image on a drum, which attracts toner powder and transfers it to paper.
Uses: Offices, schools, business printing.
Advantage: Fast and durable prints; good for high-volume work.
Disadvantage: Expensive to buy; toner cartridges costly.
Light emitting diode (LED) screen - how it works + function + examples + advantage/disadvantage
Function: Displays images using LEDs as light sources.
How it works: Thousands of tiny LEDs light up individually to form images.
Uses: Televisions, computer monitors, advertising boards.
Advantage: Bright, energy-efficient, long-lasting.
Disadvantage: More expensive than LCD; can suffer from “burn-in.”
Light crystal display (LCD) projector - how it works + function + examples + advantage/disadvantage
Function: Projects images using liquid crystal display panels.
How it works: Light passes through three LCD panels (red, green, blue), which combine to create full-color images.
Uses: Classrooms, meetings, home theaters.
Advantage: Good color accuracy and brightness.
Disadvantage: Can have lower contrast than DLP projectors.
Liquid crystal display (LCD0 screen - how it works + function + examples + advantage/disadvantage
Function: Displays text, graphics, and videos.
How it works: Uses liquid crystals that change alignment when an electric current passes through, controlling light from a backlight.
Uses: Monitors, laptops, TVs.
Advantage: Thin, light, low power usage.
Disadvantage: Limited viewing angles; slower response time than LED.
