Input and Output Devices
Hardware · 4 question types
Exam Frequency Analysis
Past paper frequency (2018 to 2024)
This topic accounts for approximately 3% of your exam marks.
Typically tested as 'give one use of…' or 'describe how this sensor works' questions.
| Device | What it does | Typical uses |
|---|---|---|
| Monitor (LCD / LED screen) | Displays text and images on a flat panel using liquid-crystal cells lit by LEDs or a backlight | Desktops, laptops, smart TVs, smartphones |
| Inkjet printer | Sprays tiny droplets of liquid ink onto paper | Home and small-office printing of colour photos and documents |
| Laser printer | Uses a laser to fuse fine powder (toner) onto paper with heat | Office printing of large volumes of documents |
| 3D printer | Builds a solid 3D object by depositing thin layers of plastic (or other material) one on top of another | Prototypes, custom parts, medical implants, education |
| Speakers / headphones | Convert a digital audio signal into analogue sound waves | Music, voice calls, alerts |
| Projector (LCD / DLP) | Throws an enlarged image of the screen onto a wall or projection screen | Classrooms, meeting rooms, home cinema |
| Actuator | Converts an electrical signal into physical motion (e.g. opening a valve, turning a motor, moving a robotic arm) | Robotics, factory automation, washing machines, automated systems |
An is the opposite of a . A sensor turns a physical property into a digital signal (input). An actuator turns a digital signal into a physical action (output). Together they are the core of every automated control system (topic 15).
Classifying devices as input or output
What comes up: a list of devices is given and you must circle or tick the ones that are output devices (or input devices). Common distractors are included deliberately.
Write: output devices include printer, speaker, actuator, screen/monitor, LED. Input devices include keyboard, mouse, microphone, digital camera, sensor, barcode/QR scanner, touchscreen (its touch layer), biometric device.
Watch out: a sensor is an input device, not an output device — it sends data into the computer. An actuator is an output device — it receives a signal from the computer and produces a physical action. Mixing these up is the most commonly penalised error in this question type.