Input and Output Devices
Input and output devices allow users to communicate with a computer.
- Input devices send data and instructions to the computer.
- Output devices present the processed information to the user.
For example, when you type using a keyboard, the keyboard sends input to the computer. After processing the data, the computer displays the result on a monitor as output.
How Input and Output Devices Work
A computer follows the Input–Process–Output cycle:
| Input | Processing | Output |
|---|---|---|
| The user enters data through an input device. | The CPU processes the data according to instructions. | The result is presented through an output device. |
For example:
- A user types a calculation using a keyboard.
- The CPU processes the calculation.
- The result appears on the monitor.
This cycle is used whenever a computer receives data, processes it and produces a result.
What Is an Input Device?
An input device is a hardware component used to enter data and instructions into a computer.
Input can include:
- Text
- Numbers
- Images
- Sound
- Video
- Movement
- Biometric information
The input device converts the user’s actions or physical information into a form that the computer can understand.
Examples of Input Devices
| Input Device | Main Use |
|---|---|
| Keyboard | Enters text, numbers and commands |
| Mouse | Controls the pointer and selects items |
| Scanner | Converts physical documents into digital form |
| Microphone | Captures sound and voice |
| Webcam | Captures images and video |
| Joystick | Controls movement in games and simulations |
| Barcode Reader | Reads barcode information |
| Biometric Scanner | Captures fingerprints or other biometric data |
Input devices do not normally present the final result. Their main purpose is to provide data to the computer.
What Is an Output Device?
An output device is a hardware component used to present processed information from a computer to the user.
Output can appear in different forms, including:
- Visual information
- Printed information
- Sound
- Video
- Physical movement
The output device converts the computer’s processed data into a form that people can understand.
Examples of Output Devices
| Output Device | Main Use |
|---|---|
| Monitor | Displays text, images and video |
| Printer | Produces information on paper |
| Speaker | Produces sound |
| Headphones | Provide personal audio output |
| Projector | Displays computer visuals on a large surface |
| Plotter | Produces large and highly accurate drawings |
Output devices do not normally send user instructions to the computer. Their main purpose is to present the results of processing.
Devices That Perform Both Input and Output
Some devices can perform both input and output functions.
Touchscreen
A touchscreen displays visual information and also receives input when the user touches it.
Headset
The headphones provide audio output, while the microphone captures audio input.
Multifunction Printer
A multifunction printer can scan documents as input and print documents as output.
Network Interface Card
A network interface card sends and receives data between a computer and a network.
These devices are known as input/output devices or I/O devices.
Difference Between Input and Output Devices
| Feature | Input Device | Output Device |
|---|---|---|
| Purpose | Sends data to the computer | Receives processed data from the computer |
| Data Direction | User to computer | Computer to user |
| Main Function | Enters data and instructions | Presents processing results |
| Data Conversion | Converts user actions into computer-readable data | Converts computer data into a human-understandable form |
| Examples | Keyboard, mouse and scanner | Monitor, printer and speaker |
The simplest way to remember the difference is:
Input goes into the computer, while output comes out of the computer.
Why Are Input and Output Devices Important?
Input and output devices are important because they:
- Allow users to control a computer
- Make communication between users and computers possible
- Help users enter different types of data
- Present processing results clearly
- Support work, education, communication and entertainment
- Make computers accessible to people with different needs
Without input devices, users could not provide instructions to the computer. Without output devices, they could not see, hear or use the results.
Input and Output Devices in Everyday Life
Input and output devices are found in many electronic systems.
At an ATM
- Keypad and card reader provide input.
- Screen and receipt printer provide output.
In a Supermarket
- Barcode scanner provides input.
- Display and receipt printer provide output.
On a Smartphone
- Touchscreen, microphone and camera provide input.
- Screen, speaker and vibration motor provide output.
In a Classroom
- Keyboard and microphone provide input.
- Monitor, projector and speakers provide output.
Topics Covered in This Chapter
The following pages explain input and output devices in greater detail:
Input Devices
This section covers devices used to enter data into a computer, including:
- Keyboard
- Mouse
- Scanner
- Microphone
- Webcam
- Joystick
- Light pen
- Trackball
- Touchpad
- Barcode reader
- QR code reader
- Biometric scanner
- Optical character reader
- Optical mark reader
- Magnetic ink character reader
Output Devices
This section covers devices used to present information from a computer, including:
- Monitor
- Printer
- Speaker
- Headphones
- Projector
- Plotter
- Braille display
- 3D printer
Frequently Asked Questions
What is an input device?
An input device is a hardware component used to enter data and instructions into a computer.
What is an output device?
An output device is a hardware component used to present processed information from a computer.
What are five examples of input devices?
Keyboard, mouse, scanner, microphone and webcam are common input devices.
What are five examples of output devices?
Monitor, printer, speaker, headphones and projector are common output devices.
Is a touchscreen an input or output device?
A touchscreen is both an input and an output device. It displays information and receives touch-based instructions.
Is a printer an input or output device?
A printer is an output device because it receives processed data from a computer and produces a physical copy.
Is a scanner an input or output device?
A scanner is an input device because it sends digital information from a document or image to the computer.
Conclusion
Input and output devices connect users with computer systems.
Input devices, such as keyboards, mice and scanners, send data and instructions to the computer. Output devices, such as monitors, printers and speakers, present processed information to the user.
Some devices, such as touchscreens and multifunction printers, perform both input and output functions.
In simple words, input devices help users communicate with the computer, while output devices help the computer communicate with users.
